The Gal Who Was Meant to Confess to Me as a Game Punishment Has Apparently Fallen in Love with Me is a Manga/Manhwa/Manhua in english language, ROMANCE series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Barato Nanami, a toned-down version of the gal at the top of the school pecking order, lost a game of cards and now has to confess to a guy in her class as a punishment. Misumai Youshin, who is a loner with no friends was the chosen guy but he knows about the punishment! It should have been a game punishment, but will Nanami grow feelings for Youshin...?