Holding up his hand as if he were swearing an oath he said simply, "I promise nothing." Jace didn't really cry. Nothing macho about it, the situation just didn't really come up. After all, whenever he'd start to feel sad he'd just stop feeling sad and feel awesome instead, it was just how he was. Holding up his hands in a basic boxing stance he began to bounce lightly from foot to foot, just getting into his basic fighting groove here.
"Ya know, sexism aside, I can honestly say I've never really fought a girl before. My sense of chivalry is really not making this easy right now." He was quite sure that she could kick his ass, still, he really didn't want to get in a stray punch and accidentally break this little girl. And she was little, Jace was now getting a proper image of that as he sized her up. Sure she could probably beat him in the long run, but Jace didn't do long run fights. He was in there, he one shotted someone, and then he was out before the cops got called. It probably wouldn't do for him to knock this girl out before he could charm his way into her pants.
Remembering exactly what kind of fight this was supposed to be, Jace focused for a second and let some flames run over his hands. The flames wouldn't really do much to her, but he had to start learning to keep his concentration up in these circumstances somehow.