A 2006 Korean movie by Moon Geun-young. Made me cry my eyes out once again...

Summary:
Julian has lived off with the money he lures from his rich female customers. But now he faces usurious debts from a hasty expansion of his business, and he will be killed unless he clears the debt in one month. The only way to save himself is to pretend to be the long-lost brother of an heiress and kill her to get her huge fortune. Min, the blind heiress, cold-hearted like Julian, slowly opens herself to him, and he, too, falls for her. But Julian has to pay his creditor and what makes it worse for him is that the illness that took Min’s eyesight relapsed, threatening her life.