Oouso Swing Manga

Oouso Swing summary:

From Rainy Sunday: "Everyday, no matter what, we tell some sort of lie." Shirose Sayo has always been mildly interested in Saeki Aoi, mainly because he's different from the other guys in her class. However, upon graduating middle school, Sayo's image of Saeki is destroyed and she finds he is not the mature young man she thought he was. A year later, they meet again by chance through a group blind date. They clear up their misunderstanding and become friends... but there's one uncomfortable issue. Saeki is in love with Mina, the girlfriend of Daichi, Sayo's older brother!