I like a girl, but she told me twice that "we are not suitable". What should I do?

I advise you to give up. You like her very much and treat her well. If you persist for so long, she will agree to associate with you out of conscience, but she may have a good impression on you or a little like you in her heart. But there is always a place in her heart that rejects you, such as not liking you touching her. Over time, she will become more and more exclusive, and she will break up with you again. She advised you not to waste money and time on her, because she didn't want to feel guilty. She doesn't want to feel sorry for you. If you insist, I support it. I just hope that the result of your persistence is not what I said!