Kanojo ni Shitai Joshi Ichii, no Tonari de Mitsuketa Amari-chan

彼女にしたい女子一位、の隣で見つけたあまりちゃん

by Neruzo Nemaki, Yuuji Yuuji

Fukusuke, a nice but plain guy, falls in love at first sight with the most beautiful girl in class, Yua. However, the one rumored to be with Yua is Fukusuke's best friend, the basketball ace, Yuusei. He is resigned to unrequited love as a background mob character, until he meets another super cute girl, Usuba Amari, who doesn't stand out because she is overshadowed by Yua. “Um, w-would you be my friend?” Fukusuke and Amari, caught in a similar situation, decide to start practicing "how to act normal" together. (Source: Kadokawa, translated)