Hesitance to speak where she could be overheard. Or she could be naturally shy, but what would make her act like that when her sister was supposedly more outgoing?
Or it could just be nerves from talking to an officer, even if she hadn’t done anything wrong.
Itachi must keep his avenues open, but finding somewhere comfortable for her to speak is priority, and so he gives her an easy smile with a nod, motioning with his head towards the side of the house, drawing a brow up in question. That should be fine? Or she can move somewhere, and he can follow.