I think firstly, I’d try to identify what feeling that person brings up in you. Then ask yourself if it’s true of that person & give yourself examples. It could be that person is triggering you & have a likeness in some way to someone else in your past. Then I’d ask myself if this person has any traits that are the same as you. If after that you come up with nothing, then go with your gut feeling & avoid them. We all have a gut feeling for a reason.