i am looking the manga i had read about 5-6 years ago but didnt finish since it wasnt complete at that time. it was about a depressed boy(student) who won something like a tournament hosted by god and was given a wish which would come true, then he wished for the world to end. But god gave humans hope, that who so ever changes his mind within a certain time then the world would not end. then here comes female protagonist which is an author specializing in romance whom which was entrusted by the government to change his mind.
it has a one-shot vibe to it. if it is a one shot then it is going to be really difficult to find the name to this after some googling NoWhere Boy https://www.mangaupdates.com/series.html?id=68474