Madeleine (2003)

Description:

Old high school friends Ji Seok and Hee Jin, who are now in their mid-twenties, meet by random chance. Hee Jin suggests that they start dating for a month and if they haven't fallen in love by then, they should go their separate ways. Ji Seok is apprehensive at first, but then agrees to go along with this unusual arrangement. (Source: AsianWiki)