MY LOVE STORY WITH YAMADA-KUN AT LV999

Akane Kinoshita, a female college student, faces the absolute worst situation when she ends up breaking up with her boyfriend after he has an affair with a woman he met playing an online game. While relieving her stress by rampaging through the open hunting grounds of an online game, Akane spills everything about her heartbreak to “Yamada”, a player she met by chance who happens to be in the same guild. “I don't care,” is his curt reply. But when Akane gets a makeover and joins an offline event to get back at her ex-boyfriend, she hears those dreadful words again. And that was Akane's fateful encounter with “Yamada”─！ (Source: Crunchyroll) — Description from AniList community (anilist.co).