Kase still doesn't see anything wrong with what she's done. She's even making fun of Yamada's reaction... And Fukami should have seen the hickey, but still doesn't reconsider anything and insted moves forward with her confession.
I thought I was reading Yamada to Kase-san, turns out I actually got lost in Kuzu no Honkai.
I'm not sure if this is a confession in the way you're talking about, as much as she's coming out to Kase, combined with an explanation why she's been so off for months.
Remember, Kase already told Fukami she's dating someone in chapter 20 (previously she though Kase had broken up). Same chapter where Fukami finally starts to realize she likes Kase as well, as she was thinking of how many girls seem to be fans of Kase.
last edited at Apr 3, 2023 4:55PM