
Yuki Toyama, an introverted loner, has a secret he hasn't told anyone. It is that he and his classmate Yuzumi Takai are "sex friends." It was supposed to be a purely physical relationship. But when Marika Uehara, a popular girl in the class, began to show interest in Toyama, their attitudes began to waver. (Source: Sneaker Bunko, translated) Note: Chapter count includes 3 epilogue chapters.
Saenai Boku ga Kimi no Heiya de Shiteiru Koto wo Classmate dare mo Shiranai is a Japanese novel of 287,745 characters, with 8,353 unique words and 1,702 different kanji. Its difficulty rating on Jiten is easy, 2.0 out of 5. The full vocabulary list ranks all 8,353 words by how often they appear, and you can study them on Jiten or download them as an Anki deck.
Here are some of the words that appear most often in this media, as well as a sample of its rarer vocabulary.