It is a truth universally acknowledged that a twice-divorced man in possession of a billion-dollar-plus fortune must be in want of a stunner of a wife. So it should come as little surprise that on April 26, Donald Trump ended his five-year apprenticeship with model Melania Knauss by popping the big question. Her response? Yes, of course. "I met him, and the sparks fly," says Knauss, 33. "It was chemistry."

Not that Knauss exactly laid a breadcrumb trail to her door when the pair met at a party in 1998. "She wasn't easy," says Trump, 57. "That actually attracted me to her." The multilingual Knauss, who grew up in the Slovenian capital of Ljubljana, stood by his side as Trump had the season of his life, first with his NBC show The Apprentice, then with his new book Trump: How to Get Rich, which is climbing the charts. "I believe strongly in the man or woman behind the other," says Trump. "I've seen people get with the wrong person, and they become unsuccessful. She makes my life easy."

And he makes her life comfortable. Gem experts estimate that Knauss's engagement ring, a 12-carat, emerald-cut diamond with tapered diamond baguettes, is easily worth $1 million. "It took a couple of visits to [Trump's] office to pick exactly the right size and shape," says Jeffrey Rackover, vice president of the luxury diamond house GRAFF and a longtime friend of Trump's. "He was very involved."

While Knauss, who has never been down the aisle, praises Trump's "amazing taste," she professes to want a modest wedding. "I like private, intimate," she says. She also likes Trump's four kids (three by first wife Ivana, 55, one by second wife Marla Maples, 40). "I want a family someday," Knauss says. "He is an amazing father." And an easygoing guy. "We've never had a fight," Trump maintains. Sounds like neither will be getting fired anytime soon.