Yamero Suki ni Natteshimau

Matsura is a calm, composed high school boy who's always lived his life putting up a front. He's good at reading people and can easily see through their true nature, but for unknown reasons, he's constantly approached by Kyuuragi—a beautiful girl with pigtails who's part of the popular group! Whether it's intentional or not, her playful and cunning actions keep throwing him off, and before he knows it, Matsura is yelling, "Stop! I'm falling for you!"

(Source: MANGA Plus)