She’s beautiful, spirited, and posh. PEOPLE examines how 24-year-old Cressida Bonas has captured Prince Harry’s heart – and why the marriage buzz grows louder as the longtime bachelor and his girlfriend of more than a year take their romance public. With condolences to aspiring princesses everywhere, there’s no use softening the blow: at 29, the World’s Most Eligible Bachelor is truly, madly, deeply in love – and according to several friends and Palace insiders, Bonas has lost her heart to the ginger-haired prince. Easygoing, artsy, model-gorgeous and from a colorful blue-blooded family, “she’s lots of fun, and there’s nothing flashy or pretentious about her – there doesn’t need to be,” says a source close to Princess Eugenie, 23, who is among Bonas’s best friends and the one who introduced the couple in July 2012.

After keeping the romance out of the spotlight for much of the past year, the pair have recently stepped out on a series of public dates, including a James Blunt concert on Sept. 30 and an evening performance of The Book of Mormon in London’s West End on Oct. 1. “They are coming out of the shadows,” says a longtime observer. Everyone from the British newspapers to betting houses have taken note (current odds of an imminent engagement are 8 to 11), with one source close to Cressida’s family summing up a popular sentiment: “They are quite perfect for each other.”

After years of playing the field, the erstwhile party prince and rebellious younger brother to William, 31, “has matured enormously,” says Penny Junor, author of an upcoming Harry biography. Following two tours of duty, “Captain Wales,” as he is known in the British Army Air Corps, “has a more serious outlook after Afghanistan,” she adds. “That changes a person.”

So does finding the right love match. Affectionately known as “Cressy,” “Smally,” and “Snoops” to friends and family, the free-spirited Bonas is a Leeds University graduate and modern dancer who shares with Harry a love of adventure, indie rock, and late-night clubbing. “She’s really sweet, easy to talk to, and really funny,” says Becci Whelan, 23, who recently completed a postgraduate degree in dance studies at London’s Trinity Laban Conservatoire of Music and Dance with Bonas. When it came to her famous boyfriend, she was unfailingly discreet. “You would never have known that she was going out with Prince Harry,” says Whelan. “She didn’t talk about it.” She’s a fixture in the London nightlife scene populated by the rich and aristocratic. “She went to a lot of events, but that’s because of who she was,” says Whelan. “I wouldn’t say she was a party girl as such. She was always up for fun, but I wouldn’t say she’s out doing shots every night of the week.”

In fact, her patience with Harry’s wild side may have helped win him over. Despite the fact that he notoriously partied in Las Vegas in August 2012 – naked billiards, anyone? – within just one month of their first known date at a film premiere, she took the incident in stride. And her ease with the royal family brings a comfort level for Harry, who shared his frustration earlier this year at finding someone “willing to take on the job” of royal-to-be. “She really does know how to conduct herself,” says the Cressida family source. “She is not socially ambitious. She doesn’t need the trappings of a prince – but she probably enjoys them.” Says an insider: “The Queen and royal family like them to wait a bit – to test the relationship.” But given how carefully Harry has shielded the relationship, friends say he is planning for the future. “He is being very protective of her,” says the Cressida source. “I would imagine he is very keen and doesn’t want to blow it.”

More on Prince Harry & Cressida Bonas appears in the new issue of PEOPLE; on newsstands everywhere now.

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