[Or more likely "Sebastian, be sure to win the ice witch's favor so that when the time comes, she'll happily build me my own castle." Just please don't try any of your pick-up lines on her.]
I see. [Her palace, is it? Everything in her speech to her demeanor screams nobility. He'll have to be on his best behavior after all.] Well then, permit me to compliment you on your magnificent decor. [Lays it on thick, yes, but the place truly is magnificent.]
The delicate details alone...you'll have to give me the name of your contractor, My Lady... [Quid pro quo, Elsa. He even gave you his rank.]