theres a classic " The liar and his Lover"
It has both a japanese and a korean version . OG is a japanese manga
Read this : People might find it a bit disturbing because in the japanese version. that is both the movie and the manga. theres a 9 years gap. the guy is 25 and the girl is 16. yes shes underage. but its normalized in japan. this kinda age gap , even when the younger one is 16-17 is somewhat okay. even marriage is allowed with parental consent for the younger one. but a lot of people might find it disturbing . it is legal in japan for a 16-17 year old to be in a parental approved relationship with someone who is an adult, preferably of nearby age. but sexualization of the relationship is not usually approved . the korean version does not have that problem tho, because in korean law its considered pure pedophilia and statutory r+pe. in the kr version the girl is 19 and the guy is 26 i guess . but i would say give the manga and film a go to. its a classic manga. one of my very first