“I was not at all shy about asking, almost always before we met in person, questions like, ‘What sort of commitment are you looking for?’ and ‘What happened in your past relationships?’ and ‘What do you want out of life?’” she said. “Questions that might be a little intense for a first or even second date.” It helped, she added, that she could ask these things over text. “If these questions were intimidating or didn’t resonate—and for many they didn’t—that was fine,” she said. “That told me this was not a person I’d want to be with, or who would want to be with me.”

She eventually connected online with William Vanderstrand, and they spent several hours talking on the phone before they ever got together in person. “He proposed after nine months,” she says, and they got married in a manor house in the English countryside.

Online dating has been criticized for lots of things. Some say that it encourages a “meat market” approach to romance, offering too much choice—and too much temptation to constantly look for something better. Others deride it as nothing more than a platform for arranging quick hookups. But there is now evidence that online dating could, in fact, be improving the likelihood of romantic compatibility—and making marriages stronger.

According to a 2016 Pew Research Center poll, half of all Americans know someone who uses online dating or has met a spouse or serious partner that way. That includes adults ages 18 to 24, who arguably have the greatest chance of interacting with a potential partner in person—whether through school, early careers, the bar scene or friends of friends.

Researchers from the University of Chicago found that more than a third of U.S. marriages between 2005 and 2012 started online—and that online couples have longer, happier marriages. The study of more than 19,000 participants, published in 2013 in the Proceedings of the National Academy of Sciences, found that the “relationship quality” of partners who meet online may be higher—and the rate of separation or divorce lower—than for partners who meet offline.

According to the study, the rate of marital breakups for respondents who met their spouse online was 25% lower than for those who met offline. The researchers suggested that a greater pool of potential spouses might give users more options and allow them to be more selective.

They also found that more anonymous online communications produced greater self-disclosure—and stronger feelings of affection—than face-to face communications, laying the foundation for more enduring relationships. A 2011 paper published in the journal Communication Research reached a similar conclusion. In a study of 85 participants conducted by researchers at Cornell University, opposite-sex participants were assigned to a face-to-face exchange, an online exchange with the addition of a webcam, or a text-only exchange. Researchers found that the text-only couples made more statements of affection than either of the other groups and were more comfortable sharing intimate information.

“Humans started down a path to becoming isolated the moment the first person put on the headphones of their Sony Walkman,” says Eric Resnick, a professional dating profile ghostwriter in Orlando, Fla., who met his wife online. “We hide in our phones. Online dating sites and apps make it possible to reach out in a way that doesn’t make most people uncomfortable.”

It also helps them open up. “Most online daters have a tendency to discuss the reasons their last relationships have failed without even realizing it,” says Mr. Resnick. “This gives savvy singles a chance to peek into the actual mind-sets of potential partners and not just into their favorite food or the last book they read.”

“Relationships only last when your goals are aligned,” says Amy Schoen, a life and dating coach based in Washington, D.C. Online dating reveals those goals “up front and center,” she said. It requires singles to understand and articulate their own values and goals in a way many never have. This is important because, as Ms. Schoen put it, “knowing yourself is the first step in knowing what you need from a good partner, and how to be one yourself.”

Eric, a 45-year-old graphic designer in Baltimore who met his wife five years ago on the dating site Plenty of Fish, says that before he started dating online, he’d always chosen a partner based on looks. “I figured if the attraction was strong enough, any issues we might have could be overcome,” he says. “Those relationships always failed. Online dating, though, forced me to consider, and write down, my values, which also made me more aware of the importance of knowing the values of others.” He and his wife, he says, “agree on most everything.”

Though many singles may view dating online as an efficient way to find someone who meets their specific criteria, dating apps can, in fact, open up users to a wider range of potential partners. A 2017 study by researchers at the University of Essex in the U.K. and the University of Vienna in Austria, published in the social-science journal SSRN, found that marriages created online were less likely to break up within the first year than marriages that started offline. The researchers suggested that people who meet online are more likely to be compatible precisely because they’re matching with partners they might have otherwise overlooked. They noted, for instance, that a rising rate of interracial marriages corresponded with the launch of Match.com, Tinder and OkCupid.

“The number of potential dates online can help people broaden, rather than limit, their own definition of their likes and dislikes,” said Carrie Krawiec, a licensed marriage and family therapist in Troy, Mich. “It can challenge some rigidity about things that once seemed important. I often tell my clients it’s like home buyers who go in saying they must have a finished basement or a three-car garage but make a concession when a house with a two-car garage has a master bedroom they can’t live without.”

Over time, said Ms. Carbino, people relaxed their preferences and were more likely to give a chance to someone who wasn’t exactly what they thought they were searching for. “This isn’t ‘settling,’” she said. “It’s learning.”