Will Aoba Johsai's Backup Setter Fall for a Volleyball Fool?

My name is Kotobuki Yuu. I’m the trumpet section leader and deputy club president of the Aoba Johsai Symphony Orchestra, and in everyone’s eyes, I’m a perfect high school girl: emotionally stable, understanding, considerate, and gentle. In reality, none of those words describe me. My greatest wish in life is for every troublemaker to disappear from this world. Everyone gets the wrong idea about me for one simple reason: I’m good at pretending. But, as the saying goes, “If you walk by the river, sooner or later you’ll get your shoes wet.” One day, my [true self] was witnessed by my classmate, Oikawa Tooru. Luckily, by a twist of fate, I already knew he and I were the same kind of person. So I leaned close to Oikawa’s ear and whispered, “Oikawa, you wouldn’t want anyone else finding out your secret, would you?” [Before reading] 1. This story features crossovers with lots of music anime, but that won’t affect your enjoyment. 2. This is my take on Oikawa Tooru. Sorry if he’s out of character. 3. I’ll add more if anything comes to mind. Theme: Haven’t thought of one yet