Help changing beliefs about an insufferable boss

I go through serious bouts of wanting to quit my current job, usually when I interpret my boss’s behavior as unfair or unreasonable or downright mean. I know it’s in my best interest to love this job/this boss before I leave. However, I’m having a hard time believing that she is lovable. I’ve got a lot of “truths” about her which I know are beliefs/manuals and not circumstances. How do I get to a new (positive) belief about a person after so much “evidence” about their negative traits?