This is not known to the mademoiselle--or not directly known, perhaps it is guessed in a certain way, since he has used it upon Wysteria, on occasion--but the smile that Val gives her is un sourire du compartiment privé. It is normally given only to one's friends at the end of a very long and occasionally tiresome party, full of people one only half wants to see at best, and is obligated to entertain at middle-worst, and sociably loathes at the very worst. It might also be given over a pile of maps and towers of empty wine glasses and snack plates, or over a campfire in the middle of a sweltering and dense jungle, or in the back of a muddy tavern--or, apparently, in a small cabin upon a ship on a return journey from deepest Orzammar.

Un sourire du compartiment privé isn't wielded with any sort of purpose. In fact it occurs only naturally, by mistake. As in: here, when Wysteria laughs, and Val feels that he has somehow won some prize.

Really, it is nothing.

"Of course it is not attractive. It is miserable! I would not waste your time, mademoiselle, upon objects that are merely attractive. How tiresome and predictable. Any attractiveness of a Brankanian figure comes of its symbolism. It is for this reason that it was selected in particular for you," no, wait, swiftly correcting, "r, your little mansion. And I suppose for you by extension."

Really: it is nothing.