And based on Jyn's reaction to that bit of information, they will never find out!

Cassian's eyebrows go up as if to say but you were thinking about it because he does know her. He knows her, and she can read him like a book, and it would be terrifying back home but they're here where it's comforting instead.

He'll worry about what it all means later (of course). For now he can relish the comfort. Somewhat.

"Alright then. Jyn Erso, I formally invite you to dinner. Tonight and any other; a standing invitation." He hopes she doesn't expect him to put it on embossed paper, or something.