I Was Your Game, Now I'm Your Regret

Risch heir Sawyer bets he can make Esther, a girl from a modest background, fall for him in 30 days. He hides his wealth and fakes a terminal illness to test her love. Unbeknownst to him, Esther has stomach cancer too and gives up her treatment for him. Then she discovers the truth: their romance was a cruel bet. Heartbroken, she walks away. Only later does Sawyer learn she is a wealthy heiress. By then, she has found true love with Ethan, and his regret comes too late.