Ore wa Shiranai Uchi ni Gakkouichi no Bishoujo wo Kudoiteita Rashii: Baito-saki no Soudan Aite ni Ore no Omoibito no Hanashi wo Suru to Kanojo wa Naze ka Tere Hajimeru Chapter 5
There might be spoilers in the comment section, so don't read the comments before reading the chapter.
Ore wa Shiranai Uchi ni Gakkouichi no Bishoujo wo Kudoiteita Rashii: Baito-saki no Soudan Aite ni Ore no Omoibito no Hanashi wo Suru to Kanojo wa Naze ka Tere Hajimeru Chapters