Tensei Shitara Slime Datta Ken is a Manga/Manhwa/Manhua in english language, Shounen 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

A man is stabbed by a robber on the run after pushing his coworker and his coworker’s new fiance out of the way. As he lays dying, bleeding on the ground, he hears a voice. This voice is strange and interprets his dying regret of being a virgin by giving him the [Great Sage] unique skill! Is he being made fun of?