Yamero Suki ni Natteshimau

Matsuura, a high school boy, has always lived his life by putting up a front. Easily able to discern the true nature hidden behind others' smiles, he encounters a formidable opponent in the form of a cheerful, twin-tailed beauty named Kyuuragi. Whether it's intentional or innocent, her every move and gesture is cunningly calculated, catching Matsuura off guard... "Stop it! I'm going to fall for you!!!"

(Source: Shueisha, translated)