My Boyfriend Is Type-B (2005)

Ha-Mi (Han Ji-Hye) is a university student who believes in destiny and true love. She meets Young-Bin (Lee Dong-Gun) by chance and falls in love with him at first sight. Unfortunately, Young-Bin has blood type B, which is believed to be undesirable for Ha-Mi's blood type A. Young-Bin, though, woos Ha-Mi with presents, but he then shows a cheap and selfish side. Ha-Mi decides to break up with him. Young-Bin realizes he loves Ha-Mi and tries to win her back.