Happy Together (1989)

Christopher leaves to pursue a career in writing. A computer mixup assigns him to share a dorm room with Alex, whom he presumes is another guy--but "Alex" is the beautiful, outgoing Alexandra. At first she gets on his nerves by partying and being with many different guys. While Christopher tries to get another roommate, Alex helps him in different ways by improving his love life and writing ability. They gradually fall in love with each other, but Alex has a boyfriend, Slash, who comes back for her. When Slash puts her name on the wall of a men's bathroom, she realizes she is better of with Chris.