決して
けっして · kesshite · JLPT N4 · adverb
never
決 = decide + して = doing: decidedly, with a negative verb = never
決して comes from 決する (to decide, settle). Literally: having settled it. It always pairs with a negative verb: 決して忘れない = decidedly not forget = never forget. Sound hook: kesshite is like a firm case shut, the matter is closed.