How can I rekindle the relationship with the girl I like?

I think you should be straight-forward. Tell her you've felt distance between the two of you and ask if anything is wrong. Encourage her to be open and honest with you by being open and honest with her. It's frustrating to feel that way and not know what happened, and it isn't fair on her part if she isn't explaining her behavior, particularly if it involves you.

You can't make anyone do anything. There's something she's afraid to tell you for some reason. Just tell her you want to know the truth and reassure her that she can be honest with you. It's only fair. The relationship may not work after this but at least the truth will finally be out in the open for you to deal with head on.