[That first, confused muttering of her name is entirely accidental, as Bucky mulls over why the name, as well as how she looks, seems strangely familiar. But seeing Elsa's response reminds him -- that's the name of her sister, the one she'd been protecting since she was small. So he asks, this time with his usual politeness and proper respect her status affords (though more because of whose sister she is, than by simply being a princess).]
Princess Anna? [Despite knowing how this world gets, he can't help but be happy Elsa now has someone she cares about here, too.] I've heard 'bout you, ma'am, and 'tis real good to meet you.