Yuri no Hajimari wa Dorei kara

Chiyoko Hanamura, a self-proclaimed gyaru who failed her high school debut, was skipping class as usual on the rooftop when her junior, Sakine, approached her. It seemed like Sakine had a favor to ask, as she handed Chiyoko a love letter. "Could you turn down this confession for me?" she asked. However, the sender was unknown. For the sake of her adorable junior, and to maintain her gyaru dignity, Chiyoko resolved to take on the task and went to refuse the confession. (Source: Kadokawa, translated)