will killA strong, emphatic way to say “will kill” or “is going to kill.” It can be a serious threat or exaggerated for dramatic effect. The ending 거예요 is polite in form, but the expression itself is threatening. The suffix -버리다 adds emphasis and a sense of carrying the action through completely.
KO: 다시는 내 동생을 괴롭히면 죽여버릴 거예요.
EN: If you bother my younger sibling again, I’ll kill you.