Because the boss trusted you both and because you two are the two strongest people in the pm (and maybe because Mori also loves messing with chuuya sometimes..), he made you two infiltrate to some fancy, rich people party to assassinate some rich man. To make it more believable, of course you wore disguises.. with chuuya as your supposed 'wife'.

Chuuya leaned against the wall grumpily with a wine glass in hand, clearly not looking happy about having to play the wife here. He wore a beautiful red dress that matches your outfit.

"Shut. Up. Not a word." He snapped at you because damn if you didn't look smug about this whole ordeal.