Kantan dakedo, Mendokusai

Yuuha (high school 3rd year) falls in love with anyone who is kind to her or shows her some affection. She is currently secretly dating Kouno, a university student and a senior at her part time job at a gas station. One day, she hears from her scary junior at work, Kiryuu, that Kouno has another girlfriend? (Source: Shogakukan, translated) Included one-shots: Koigokoro Graph, Kawaii, dake ja Tarinai no