Oliver hesitates to say yes, because he knows himself. He knows that saying so will only end in yet another broken promise to Thea, and he doesn't want to add yet another bit of space between them, nor does he want to have her be hurt and still forgive him in the end.

"I promise to try, Speedy." Needing to make sure they're okay, Oliver pulls her into a hug and kisses the top of her head. "We're both pretty stubborn so I can't say we'll never fight, but I'll do my best."