How to change her mind?

she's trying to be nice and let you down in a way that she thinks is easy. she's diluting her feelings by not saying them directly to you.

you probably really like this girl, that's fine, but if she doesn't like you, don't try to convince her since 1. it probably wont work out given her stubbornness 2. you'll be loose a piece of yourself trying to appease her wishes and views of you 3. she'll probably cheat on you.

however there is that slim chance that she could just be waiting for someone to "wake her up" sort to speak, but given her steadfast stance on the matter, it seems that this thought will only come to her after many slashes in your heart and many mistakes in her life.

overall, i suggest not worrying too much about this and keep it at the level it is now, only working on it when she seems willing to, otherwise you'd be wasting your time and letting yourself down.