AND YOU THOUGHT THERE IS NEVER A GIRL ONLINE?

The story centers on Hideki Nishimura, a young man who confessed to a person he thought was a girl online, only for that person to turn out to be a boy. He keeps this "black history" secret and swears to never to trust a "girl" online again. However, one day a girl online confesses to him, and it turns out she's actually a beautiful girl named Ako Tamaki. Ako cannot tell the difference between the online world and reality, and she is a loner who has trouble communicating. Hideki and his friends from his guild decide to work together to "correct" her. (Source: Anime News Network) — Description from AniList community (anilist.co).