"어머, 그랬어요? 고생하셨겠네요!"
Oh, did you? You must have gone through a lot.
(When you heard the other person saying that she/he did a hard work or experienced a hard thing, you can say this sentence to show your empathy.)
어머(Oh), 그랬어요(was that so) (did you) ? 고생하셨겠네요!
고생하다undergo hardship + 시(honorific speech) + -었겠다(when you guess the past action+ -네요(when you realize something new)