He gives her a thin smile. It's genuine enough, but there is both much that he says in the not-saying and much that it says that he trusts her with that much.

"It has been a talent and a necessity both. It pleases me to be able to use it for something that is likely to be agreeable to everyone, for once," his eyes drop and there is something both genuine and practiced about the way it makes him look more demure, like he might deign to blush if he were someone else. It's as though the expression were practiced so thoroughly that it became a natural expression. "And, perhaps, to please someone of whom I think highly."

It's a bit more... guarded of a bit of flirting than some of his earlier, more honest but less flattering attempts had been. But this, too, is somewhat calculated, a small show that he can play the game when he needs to, perhaps, or perhaps some kind of leading by example. Even so, there is nothing about it that seems disingenuous.