How to ask another guy if he has a problem with you?

There are two scenarios that I would like to find the best responses to.

1. If your boss doesn't like you, how would you best ask if this is the case and why they do not like you, in a respectful, non-confrontational way?

2. A guy in a friend group you just met, with the same scenario.

I don't want to accuse and I don't want to outright challenge. I want to set a boundary and at the same time find out what I can do to not upset this person.