On the ninth day of filming Netflix’s “Mind Your Manners,” the show’s host, the Shanghai etiquette teacher Sara Jane Ho, dumped her on-again-off-again boyfriend of four years in a text message. Ms. Ho, a preternaturally poised 37-year-old who grew up on four continents and can eat a sunny-side-up egg without spilling a single drop of yolk, was in a car outside Sydney, Australia, in late 2021, on her way to perform a “Pygmalion”-style makeover for a party girl named Stephanie Osifo.

But before Ms. Ho could confront Ms. Osifo’s fishnet dresses, she had a revelation. “Here I am, telling my students how to live their best lives, and I realized I had to do the same for myself,” Ms. Ho said recently, over a breakfast of smoked salmon and eggs at the Park Lane Hotel in Manhattan. “I was just like, ‘I can’t be showing up on set with red and puffy eyes because you’re making me cry,’” she explained.

“We were pulling up to her house, and I sent off that text message, and that was that,” she said, with a knowing shake of the head, as she sliced her salmon. I got the impression that, if her hands had not been occupied with silverware, Ms. Ho might have dusted them off.

“It’s probably not the best etiquette to break up through a text message,” Ms. Ho acknowledged, noting that the pair had discussed the possibility many times.

Later, she expanded on her approach to manners. “Things are contextual,” she said. In Ms. Ho’s philosophy of social graces, the only constant is to be considerate of others. And even then, one can be forgiven for an inelegant breakup when self-actualization — and an expanding transnational etiquette empire — is at stake. “You don’t get a second time to shoot a Netflix show, right?” she said. “It’s all or nothing.”

On “Mind Your Manners,” Ms. Ho’s self-assigned mandate is ambitious: “Come with me, and you’ll know what to do anywhere, with anyone, in any situation.” Both the show and Ms. Ho’s newly international personal brand (she said her first English-language book is scheduled to publish in 2024) advance the idea of etiquette as a tool for interpersonal harmony and vehicle for self-improvement.

Ms. Ho takes a practical, international and surprisingly adaptive approach to manners. During an interview, she delivered an unprompted primer on the places and circumstances in which she might personally spit phlegm on the street.

The first episode shows Ms. Ho in a rainbow of impeccable outfits and shifting languages (she speaks four, and is fluent in three dialects of Chinese) as she coaches a diverse cast on table manners, dress codes and self-improvement. Standing in pink puff sleeves under a parasol, she guides an archery lesson; in a cerulean sheath dress with a mandarin collar, she demonstrates how to peel a banana with a fork and knife.

“I spent 10 years studying in the States, and the last 10 years living and working in China, so what I bring is an East-meets-West perspective,” Ms. Ho says on the show. She emphasizes the logic behind certain norms and bluntly rejects others she finds distasteful. (On drinking tea: “Some people keep their pinkies out to keep balanced, but it looks really pretentious. Definitely pinkies in.”)

And she offers tough love: “There are no ugly women in the world, just lazy ones,” she says during a “Mind Your Manners” hygiene lesson in which she instructs her students to smell their used dental floss to find out if they have bad breath. “Behind every elegance, there will be unglamorous hard work.”

International Sophistication Meets Occasional Raunch

“Mind Your Manners” belongs to a genre that includes “Tidying Up With Marie Kondo” and “Queer Eye,” in which charismatic life coaches act as fairy godmothers to obliging regular folks. They shower their clients with emotional affirmation and opportunities to deconstruct their insecurities and childhood traumas, plus new haircuts and advice.

Created by a Singaporean production company with international audiences in mind, “Mind Your Manners” was initially supposed to shoot in Shanghai, where Ms. Ho lives and runs Institute Sarita, the charm school she founded in 2012. With a curriculum that includes courses with names like “British Afternoon Tea,” “Pronunciation of Foreign Luxury Brands” and “Introduction to Expensive Sports,” Ms. Ho initially catered to nouveau riche Chinese interested in learning Western-style snobbery.

But China’s Covid lockdowns forced Ms. Ho to close her school’s brick-and-mortar locations in Beijing and Shanghai; she now operates out of luxury hotels, teaming up with high-end brands and private banks to entertain V.I.P.s with lessons on the art of manners. The show shot in Australia instead.

There, Ms. Ho practiced her signature teaching style, which involves meticulous self-control, international sophistication — and occasional raunchiness.

“German is a very ‘spank me’ language,” she tells a Melbourne woman struggling pronounce a porcelain manufacturer’s name. “Königliche,” the woman coughs. Standing beside a handwritten chart of tableware terminology, Ms. Ho trills with delight: “You got it! See? You think ‘spank me,’ immediately you got it.”

Ms. Ho speaks with the astonishingly posh, vaguely British accent of a person whose origin is less a place than an international pedigree. A native of Hong Kong whose father worked in oil exploration, Ms. Ho grew up in Papua New Guinea, Taiwan, Britain and the United States, where she was a boarding student at Phillips Exeter Academy. She graduated from Georgetown University in 2008, and was working on Wall Street when the stock market crashed. After a stint at a microfinance NGO in China, she attended Harvard Business School, where she busied herself “partying until dawn,” she said.

On the advice of a well-heeled friend from Indonesia, she then decamped to Switzerland to attend the Institut Villa Pierrefeu. “They call it ‘the finishing school that refuses to be finished,’” Ms. Ho explained, the last in a dying form of pedagogy that asks wealthy women to scrutinize the folds in napkins with an intensity akin to Watson and Crick studying the double helix.

Ms. Ho credits her mother, who died from cancer in 2007, for her interest in etiquette. An entertainment executive who threw magnificent Christmas parties, she regularly brought her only child on business trips. “When we went to Japan,” Ms. Ho recalled, “she’d say: ‘You remember Mr. Sato? Go over and say hi. By the way, remember in Japan, you don’t say “Mr. Sato,” you say “Sato-san.” And he has a little girl your age, so why don’t you go ask him when she’s going to come to Hong Kong and play with you?”

Etiquette, for Ms. Ho, is a dialect of socialization. “Wherever I go, I see myself as in the field,” she said. “I’m observing: ‘What are the codes of conduct here? How are people behaving?’”

When her family moved from Papua New Guinea to England, she was barred from going barefoot. When she transferred from the German Swiss International School in Hong Kong to Exeter and first encountered roundtable discussions, Ms. Ho was so intimidated by her American classmates that she didn’t speak for an entire month — until a teacher said her grades would suffer if she didn’t learn how to interject.

The show’s makeover recipients are English speakers from a variety of backgrounds.

Sometimes, cross-cultural fluency is part of the amusement: When Ms. Ho makes over a Chinese American woman who feels disconnected from her roots, she instructs her, in Mandarin, to replace her white boyfriend with a Chinese one. When the woman gasps, Ms. Ho waves her off: “Your boyfriend is Caucasian, he won’t understand what I said,” read the subtitles.

‘Everyone Was Like, Sara Ho Is Perfect’

In early December, Ms. Ho arrived on the set of “The Drew Barrymore Show” in New York City in a red Vivienne Tam dress with a ruffled neck and billowing sleeves. She wore gold hoops on her ears and, on her ring finger, a 3.23-carat oval-cut diamond. After “Mind Your Manners” wrapped, Ms. Ho embarked on a whirlwind courtship with a businessman 15 years her senior. He slid into her WeChat messages during her repatriation quarantine in Shanghai; they married eight months later.

Because of China’s Covid lockdowns, they postponed the wedding, which Ms. Ho hopes to host in her husband’s hometown, Lishui, where the couple lives part time. She recently recruited a native speaker of her husband’s local dialect for virtual tutoring; she now speaks to her mother-in-law in her native tongue.

Backstage, the arrival of her cousin Adrianne Ho — an unnervingly beautiful model who somehow made wraparound sunglasses look good — threw both women into a state of elation as they told stories from their early adulthood, when Adrianne was starting her modeling career and spent two months sharing her cousin’s studio apartment in Manhattan in 2008. Adrianne went on casting calls while Sara worked 16-hour days as a financial analyst.

“Growing up, everyone was like, Sara Ho is perfect,” Adrianne said.

“Chinese families always like to compare,” Sara interjected.

“Yeah, no, it’s not a healthy thing,” her cousin laughed.

Two weeks earlier, in California, Adrianne had been present the first time Sara was recognized as a celebrity in public. It was the day after the “Mind Your Manners” premiere, and the cousins were attending a party for Jean Paul Gaultier hosted by Kendall Jenner in a mansion in Brentwood. The cousins described how the chic blonde who managed the guest list stopped Ms. Ho in her tracks. The woman said that she loved the show, which she had binge-watched during its first 24 hours of availability, Ms. Ho recalled.

“And we looked at each other and just started screaming!” Adrianne said.

Two days before her appearance on “The Drew Barrymore Show,” Ms. Ho celebrated her birthday in New York with a cake that read, in chocolate frosting, “Happy birthday, Ho!” Citing her Sagittarian nature, Ms. Ho noted her belief in “working hard and playing hard.”

There is a moment in Ms. Osifo’s episode of “Mind Your Manners” when Ms. Ho waves a white fishnet minidress as if it were a flag. “I have absolutely no qualms with what you would wear to the bedroom or to the clubs,” says Ms. Ho, who describes the issue with Ms. Osifo’s wardrobe as one of “everyday wear.”

The episode ends with Ms. Osifo arriving at her charm-school graduation party in a flowing full-length shirtdress, which she refrains from hiking up even when she and Ms. Ho drop it low and, in unison, twerk.

Or, as Ms. Ho said over breakfast at the Park Lane Hotel, with her wrists held aloft over her plate and the tines of her fork angled just so, “There is a time and place for everything.”