Yap.Town

と思ってたのに

even though I thought…

→ と
phrase Rare #42,702
even though I thought… Expresses disappointment or surprise when reality is different from what was expected. The subject is understood from context.
JA: もう終わったと思ってたのに、まだ続いていた。
EN: I thought it was over, but it was still going.

友達だと思ってたのに！

I thought we were friends!

マーニーが日記を捜しに戻ってきたと思ってたのにえー

I thought Marnie had come back to look for her diary, but… huh?

— When Marnie Was There (2014)

友達だと思ってたのに。

I thought we were friends.