Cora knows the answer, despite the fact that Stiles doesn't want to say it. He's not exactly subtle. Or maybe she's just quick to an assumption. Either way, she leaves it, for the moment. His love life isn't exactly one of her priorities, anyway. Technically, it probably isn't any of her business either.
"Exactly, you get it." She can't help it. Cora doesn't have many fond memories of Beacon Hills anymore, not considering what happened. And the place attracts not only insanity, but drama and everything supernatural under the sun, which just complicates life...completely.
Cora doesn't know the answer to Stiles' question, not really. Does she want to leave Derek again? No. Does she really want to be here? No. So, here she is. "For now, at least. My brother's here." And that's the best reason to be here. Cora grabs another bit of the pastry she's working on and then pops it into her mouth before sliding the third one she bought toward Stiles, not sure if it's to give him something to do other than watch her, or if it's a gesture of...thanks or something for not making a comment about her sitting here.