Mayaka-neesan wa Uso ga Tsukenai

Junya is a third-year junior high school student. He's good at sports, but as for studying... he's rather terrible. Recently, he's had a problem. His childhood friend, Mayaka-neesan, keeps messing with him! Could that mean she really likes him? The beginning of a playful and deceptive romantic comedy where he's at the mercy of an ever-shifting liar!

(Source: Kodansha, translated)