When Cecilie Fjellhoy, a 29-year-old Norwegian grad student living in London, swiped right on a 28-year-old supposed billionaire diamond heir on Tinder in 2018, she thought she’d found her Prince Charming. But the supposed dream man, who called himself Simon Leviev, turned out to be a nightmare, an international con man that duped her out of $250,000 and landed her in the psych ward. SNIP Leviev’s profile showed a man who appeared to live a jet-setting life full of stylish suits and designer clothes, sipping cocktails on exotic beaches and attending high-powered business meetings. Fjellhoy had no reason to doubt...