Responses
I thought so too.
Sensei sort of brushing it off like usual cause you know he's a man but saeki barely is at a legal age and he's a teacher. So i think, receiving saeki's confession was just to give her some assurance that yes, he also felt the same way
I don't know but it seems like sensei sort of gave his feelings here
https://www.mangago.me/read-manga/kono_kyoushi_zettai_wazato/uu/to_v-3-chapter-16/pg-21/
He was taken aback for a sec and shove saeki in the desk to not see his reaction.
I know he looks suspicious but still saeki is his student