The statement isn't much of a surprise to Inigo. Gyousou's Amazingness (with a capital A for emphasis) is so obvious to Inigo that he truly wouldn't be able to understand how someone couldn't be impressed with him. The king is just one of those universally great people.

But the next part.. is a little more awkward. Mostly though since Inigo really doesn't want Taiki to have to apologize - not for anything involving him. So he quickly looks up at the other, flashing him a smile, trying to make it look as genuine as possible. (It's not really faked as much as it's intentionally done to try and reassure Taiki, anyway.)

"It's fine." And he means it! This time! It's not like he hides stuff about himself because he wants it to be secret, it's more just because he doesn't want other people to feel bad if he talks about sad things.. "If you want to ask anything, just ask. I can talk about it. What do you want to know?"