"Fair enough." He's charmed, to say the least, if not entirely won over. Give it time, Frisk. He sticks his hands in his pockets instead of clasped behind his back and it helps him look less prickly and more welcoming. Not by much, but a good enough telegraph that he isn't going to reject Frisk's offer.

"...now, I am going to explore this castle. And hopefully find some explanation."