The killer

I am a boy who liked one girl in college since 1 year … I never had a girlfriend and I am a very shy and introvert person !! I have tried to approach her to start friendship but she runs away .. Also I have tried to initiate chat but she ignored.. I am a decent nice and good boy .. We have one common friend but nothing happened … I think she like someone else but not know clearly .. Why she ignores me ? I really like her and at least want to be her friend if not something else ? How can I make her at least talk to me ? How can I clear and negative things about me if she have ?