check

ChandlerのThe Big Sleep を読んでいます。
I went to the door and looked out. The cool night breeze was blowing peacefully down the hall. No excited neighbors hung out of doorways. A small gun had gone off and broken a pane of glass, but noises like that don't mean much any more. I held the door open and jerked my head at Carmen. She came towards me, smiling uncertainly.
Go on home and wait for me, I said soothingly.
She put her thumb up. Then she nodded and slipped past me into the hail. She touched my cheek with her fingers as she went by. You'll take care of Carmen, won't you? she cooed.
Check.
You're cute.
"Check" と言うと米国のレストランで「お勘定」の意味で使いますが、上の場面はレストランではないので違う意味ですね。辞書を見ます。
・Cambridge English Dictionary: mainly US used to say yes to someone who is making certain that all the things on a list have been dealt with or included: "Did you bring your sleeping bag?" "Check." "Pillow?" "Check."
アンケートのチェックボックスに印を付けるのと同じですね。