Carter knew the rules of society. Humans and Super Naturals don't mix even though they comingled at university, it was unacceptable to speak to a supernatural. Humans were seen as the weaker species. Carter understood that she would never be good enough to even breathe the same air as some of the super naturals so when Asher Kai started paying attention to her she was wary of him. Asher Kai was a Nephilim who everyone knew hated humans. He thought they should go back to being slaves, that's all they were good for after all. He never thought he'd find himself falling in love with one but there was something about Carter that he couldn't shake.