_{[ He remembers it clear as day, as well, but he doesn't feel like the promise was broken. Not at all. That is why he is asking what she means by a broken promise.
Olivia is so silly— feeling this way over a wound in his hand and a cut over his chest. This was nothing in comparison to what he faced protecting his city and the people who are the most important to him. Though, here she is, feeling guilt from something that was out of her control. Of course she wants to go back to blaming herself for allowing the demon to possess her, which is understandable but.. ]}

Olivia.
_{[ His lips spread into a sincere smile. ]}

You cannot expect to overcome something powerful so easily. You grow— you improve yourself until you are strong, if that is what you truly desire. Strength, though. It's overrated. What you should be pursuing is what you actually want to overcome, and if that includes not being weak, so be it.

_{[ He shifts, leaning in a little closer to her and he places his hands on his knees, as if he was telling her a secret: ]}

A broken promise? I don't think so. What physical pain you caused me is worth what happened because in the end... you fulfilled the promise. You gave me an opportunity to protect what I want to protect, which I did.. because you are alive and right here before me. If I would have allowed you to go and get swallowed up by that demon, then it would have been a broken promise... and my fault.

_{[ He leans back and opens the little box, going straight for the cake and speaking while doing so: ]}

Take it as a lesson to become stronger, but only if that is what your soul truly desires. As long as you take your own path and make your own rules for yourself and disregard what anybody else says, you'll eventually find contentment with yourself.

_{[ He takes a bite of cake with his bare hands, muffling a catch-phrase from another Shounen hero: ]}
Believe it.