Look at what you said, you and her used to be quite good. She shouldn't really hate you, but she may have a little love for her brother. Think for yourself. Did you do something bad, or did she misunderstand you? I think you should also find your own reasons. The relationship between your mother-in-law and your aunt is actually not that difficult to deal with. Treat them, you must not be partial, treat them as your own family. You can take the initiative to find her, invite her to dinner, or have a drink with her, because maybe she will talk freely with you after drinking and tell you why she is dissatisfied with you. I recommend a TV series "Happy Time of Daughter-in-law" for you, which was played by Christina. It's really realistic. After reading it, it should be enlightening and helpful. Christina's sister-in-law is similar to the person you mentioned. Finally, they became good friends. You can refer to it and hope it will help you.