He's a smooth criminal and kisses Kanao, but ends up on top of her accidentally.
Left a note on her door.
Wasn't the one who confessed.
Places a foot on his chest, leans down and kisses him.
Didn't confess because she's a Tsundere.
Was kissed by Tanjiro, and the same thing happened, but I'll note they didn't do "it".
Annoys Shinobu until acknoledged.
"I love you."
"I love you, too.."
RECORDS EVERY CONFESSION AND SENDS IT IN THE MAFIA'S GROUPCHAT.