I absolutely loved this. First of all, Stefan says that she’s better than that, based on his own idea of who she is and how she is supposed to feel, comparing her to him and almost judging her for his mistakes of the past. Damon, on the other hand, says that she doesn’t want to be like this. He says it for her, because it’s about her and not about him or Stefan or anyone else. It’s about her and he knows it.
Second, look at both of her answers. She couldn’t care less about what Stefan said, and of course, her humanity is off and she is not supposed to care. But instead of giving Damon one of these sassy answers she gave everyone in this episode, she asks him how she’s supposed to be, it’s almost like she’s looking for advice. Because she trusts him and she knows he won’t judge her. Her humanity is off, the sire bond is gone and she is able to trust him and count on him either way.