ㄹ게

I'll do it — a promise to you

The speaker commits to doing something, with the listener in mind: 맛있는 거 사줄게 "I'll buy you something tasty", 전화 해둘게 "I'll go ahead and call", 다시 돌아올게 "we'll come back". Only ever first person — you cannot use it about someone else — and it always carries a hint of doing this for you or letting you know. Compare ㄹ 거야, which just predicts what will happen with no promise attached. Add 요 for politeness (해볼게요); it is written ㄹ게 but pronounced with a tense k.

Register: casual; add 요 for polite