How to apologize for the quarrel between elder sister-in-law and elder sister-in-law?

Does the subject want to ask, "How can I apologize for the quarrel between my sister and my brother-in-law?"

1, I'm very sorry. My sister's relationship with you has become tense. I know it's not your fault, but an internal problem in our family. I hope we can re-establish trust and friendly relations.

2. I know that my sister sometimes makes some inappropriate behaviors, which brings you unnecessary pressure and trouble. I am deeply sorry, because this is not what I want to see.