The Reincarnated "Sword Saint" Wants to Take It Easy is a Manga/Manhwa/Manhua in english language, Action 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

Alta is the youngest knight in history and the reincarnation of the legendary “Sword Saint”. He is dispatched to the school to protect Iris, the “Sword Saint Princess” who is the next king’s candidate, but “Please fight with me seriously”, but Iris, who is supposed to be his escort, suddenly challenges him to a fight…!