Pavam Pavam Rajakumaran (1990)

This offbeat romantic comedy revolves around Gopalakrishnan, an extremely timid young man, who works as a teacher at a parallel college in Kerala. Spurred on by his complete inability to interact with women, his friends are forced to play a prank on him. They begin posting letters to him in the name of a girl, completely unbeknownst to her. He gradually develops an intimate relationship with her, but all his efforts to meet her are in vain. What happens when he actually meets her and comes to know that she hasn't the vaguest idea of who he is, forms the crux of this insightful tale.