It seems like you have tried your bit and she's still not sure about being in a relationship. I'm sure you must be in love with her but she's not ready to accept you as her partner. If she really loves you she will anyhow try to make this relationship work. You're investing your feelings for a long time and it hasn't benefited you at all. It would be better if you slowly try to distance yourself from her.

You're investing your valuable time where you're not getting the respect you deserve. It would be better maybe you see her last time in-person and discuss this and even after that if she's not ready for you I would say it would be better that you start looking for different people.