Watashi de Doutei Suteta Kuse ni

Kota and Sakura grew up like siblings and were closer than best friends. The people around them were always saying what a perfect couple they’d make, so the two of them decided to try dating once. But in the end, neither of them developed any genuine romantic feelings for the other. After that— “Ahaha, and that was after you lost your virginity to me, too.” “Look how red your face is. So cute.” Even as Sakura teased him like that, their easy, comfortable relationship continued. But then, one day, Kota learns that Sakura has won a certain novel prize. Shocked to discover an unexpected side of the childhood friend he thought he knew so well, he soon finds himself caught up in resolving troubles involving Ui, the school’s problem child. As all of that unfolds, the relationship between the two of them gradually begins to change… (Source: Kadokawa, translated)