My girlfriend and I have reached the point of talking about marriage. As a result, her fortune teller said that we couldn't get along and asked us to break up. I can't convince her parents anyway.

The fundamental problem is that you haven't completely handled your relationship with your girlfriend.

There is only one plan now: find a way to get her family to recalculate their lives. If she chooses a fortune-telling place, you should try to get this address, and she'd better accept your recommendation (you should recommend a famous temple, otherwise you can't convince her to go, and you can't convince her that this result can overturn all the previous results), and then you can deal with the host or fortune teller in advance. I don't believe this. I can't handle your mother-in-law!

If your girlfriend is dissatisfied with you and has no confidence, you need to work hard, friend!