I Never Fall in Love with Komiyama, Maybe.

As a fifth-grader, Kakeru Komiyama is average in both academics and sports. On the other hand, Kakeru's classmate with the same last name, Eina Komiyama, is the best girl who excelled at everything. One day, Kakeru noticed a moment of weakness in Eina and became concerned about her. However, Eina suddenly transferred schools without even saying goodbye, and Kakeru moved on to become an ordinary high school boy without any particular achievements. There, he reunites with Eina, who hasn't seemed to changed at all, except for her last name... A frustrating love story between childhood friends unfolds. (Source: Natalie, translated)