Grammar
-겠-
inference about a situation
Form
Verb/adjective stem + -겠- — “must, probably” depending on context.
Function
Marks an inference or supposition based on evidence; not necessarily future time.
Why this form?
-(으)ㄹ 것이다 — “will/probably” can predict a future event; -겠- often presents the speaker's subjective assessment.
How to build it
The marker -겠- comes before the sentence-final ending: -겠어요. If -(으)시- is present, it precedes -겠-: 무서우시겠어요.
Forms not to confuse
-(으)ㄹ 것이다
많이 무서웠을 거예요. — You were probably very frightened.
Examples
많이 무서우셨겠어요. — You must have been very frightened.
많이 힘드시겠어요. — That must be difficult for you.