Without acting like he doesn't know the first thing about her.
That does well to knock her down a peg or two and lower some of those automatic defenses, reminding her that this is Han. He gets it — gets her. Even when she doesn't want him to, he always seems to find a way to get under her skin and understand her almost as if he's doing it just to spite her. It's frustrating.
(She's thankful for it. Grateful for him. Still sorry that she even contemplated for a moment being with someone other than this awkward ex-smuggler who can't dance or leg wrestle.)
"But you don't know the Force," she points out, though her tone has softened considerably. "And neither do I. That's the problem. I didn't mean to do that," a gesture towards the dance floor, "yet I did. It happened, and I made it happen without doing anything to make it happen. Do you understand?"