"Do you want her to become like them permanently? One can only take so much pretending to be something until eventually, they become it. I don't doubt her, Potter, but dark magic takes a toll on you. I've seen it destroy some of the strongest willed men I know, do you really think she'd be able to live with herself once all of this is over? Do you really think she would be able to stomach the fact that she slept with him? She can never remember what happens right? Well what happens when memories start surfacing? When she starts having nightmares and can't depict them from reality? She'll end up with a one way ticket to St. Mungo's."