*Sirius rubs his forehead, wishing Remus were here to say something--the right thing, the thing that'll make her listen instead of storm out. But at least she hasn't stormed out yet.*

Look, Rose, I'm your friend, but I'm not a--what was it you called me? I'm no knight in shining armor, all right? I know that. I've made mistake after mistake and I am trying--trying very very hard--to make fewer of them. But I think I know you well enough, and I've fucked up my life enough, to see what's going on. No one can stop you from doing what you're going to do. But I'm your friend, so I've at least got to say something.