Hello Sweetdoct247
It is very hard to deal with a situation, where one feels that one is in love with someone who isn't interested in having a romantic relationship.
However, it is also difficult to deal with a situation, where someone is in love with, or infatuated with, one, when one does not feel the same way in return.
This girl said 'no' when you asked her out, yet you keep expecting her to respond in a different way. She is formal and evasive because she does not feel as you do, and she wants to make this clear to you, because she does not feel that she has convinced you yet.
I don't think that you need to find a way to convince her that you are besotted with her; she probably knows this ~ hence the way she is behaving.
It's hard, I know, but you are going to have to accept that ~ for the present at least ~ this girl does not want a relationship with you. She is making this very clear.
This happens to lots & lots of people. You are not alone in this. You must remember, though, that for a relationship to work, both people have to care and be committed. You could not be happy with this girl, even if she agreed to date you, because she does not feel as you feel.
You won't fall in love with someone else tomorrow, because you need time to come to terms with this, but you will, eventually, find someone else and, hopefully, you will find someone who cares equally for you.
Good luck
