Most Helpful Girl
Just because you love someone, or want someone, or fancy a shag with someone, does not mean they owe you anything. A desire on your part is not an obligation on someone else's part.
She has got the right to say no to you. She is not doing anything wrong by saying no to you. If you can't handle that, I would say the problem does not lie with her. You are not entitled to have her just because you want her.