Fake promise is breach of trust, you are entitled to file a criminal case under section 415 of IPC, for "cheating", on the grounds she cheated you into having a relationship with her and spending money on her, and is now not ready to marry you.
However, you have prove that:
That she promised to marry you in the past
That you made some changes to your life, or acted based on that promise
That it led to some monetary loss
That it led to loss of your reputation and you are defamed in the society
That you faced emotional trauma which in turn resulted in some kind of loss
If she is found guilty of Cheating, then the court will only be able to order with imprisonment of either descripttion for a term which may extend to one year, or with fine, or with both.