Paavam Paavam Rajakumaran 1990 one on netflix

The film is about a parallel college teacher who owns a bizarre and timid personality which forces his friends to fool him by posting him letters in the name of a girl. 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 even had no idea about his existence, forms the crux of the story.