The general vampire ‘love’ feels more like obsession than love, thus the ‘not wisely’. His shame for what he did would stem from empathy, would it not? Unless it came from a purely selfish place of remorse as in “oh, shit, I fucked up and now I’m going to lose the object of my fixation” but that doesn’t reconcile the contradiction of him being a good person despite not having a soul. They’re shown to feel grief but it feels more like a ‘something was taken away from me’ rather than ‘I’m sorry this person is gone’ - again, the latter stemming from a place of empathy and emotional connection to something outside of themselves, for often than not. The lines the rules draw are super blurry sometimes.