만나기로 했는데

I was supposed to meet, but

→ 만나다

phrase Common #4,662

I was supposed to meet, but Introduces a meeting plan as background, often followed by a contrasting situation. The person you planned to meet can be clear from context.

KO: 친구를 만나기로 했는데 아직 안 왔어요.

EN: I was supposed to meet a friend, but they haven’t arrived yet.

솔직히 오늘도 만나기로 했는데 그걸 안다고 뭘 어쩔 수 있어?

Honestly, we were supposed to meet today too, but what good does knowing that do?

— 홍등 (1991)

어디 서 만나기로 했는데?

Where did you agree to meet?

— 엘리트 스쿼드 (2007)