There had to be some way of going about this. Hawke thought better on the battlefield than she did when it came to relationships, but there had to be something... other than the obvious 'go with your instincts' answer. That didn't work for everyone.
"Give it a little longer, but... don't do anything like shutting yourself off from him, that'd probably just make him think he's done something wrong," and from what she knew of Alistair, he'd likely do something embarrassing, or attempt something 'heroic', to try and fix things. "If he likes you as much as I think he does, he'll respect that you want to wait when it comes to... more involved things."
And if he didn't, he was going to get a royal arse-kicking from Hawke.