Viola stares down the dragon, letting her sword touch the ground and relaxing as much as she can.   They're probably a bit like dogs; don't take your eyes off of them and don't dare lose a fight if they decide to start one.   Dragons can probably talk, though, so she starts talking (admittedly in Common), "we're not here to hurt you.  And judging by the fact that you haven't started hurting us, I don't think you're here to hurt us either."