He holds her gaze. Her response is absolutely confirmation because otherwise she'd be rolling her eyes, or bringing up canoodling with Wren, or so on. What he doesn't know is how treacherous or not the ground he's standing on is.

"You and Loghain have been spending time together in a... close manner, or so his body language would suggest." Teren's seems to always be aloof even when she's not feeling aloof, so he can't go off that. "I thought it a positive sign."