ものだと思ってました

I thought that ... would; I assumed that ...

→ 物

phrase Rare #21,039

I thought that ... would; I assumed that ... Used after a clause to express a past assumption or expectation. ものだ can suggest that something is expected or taken for granted. と思ってました is a conversational contraction of と思っていました.

JA: 私たちは夕食に出かけるものだと思ってました。

EN: I thought we were going out for dinner.