ich dachte, Sie seien

I thought you were

→ ich
phrase Rare #46,556
I thought you were Formal expression. The subjunctive form „seien“ is used to report an assumption or belief about someone or something.
GE: Ich dachte, Sie seien schon gegangen.
EN: I thought you had already left.

Ich dachte, Sie seien Tom.

I thought you were Tom.

Ich dachte, Sie seien jemand anderes.

I thought you were someone else.

— Der Maschinist (2004)

Ich dachte, Sie seien sehr beschäftigt.

I thought you were very busy.

— Audition (2000)

Ich dachte, Sie seien sauer.

I thought you were angry.

— GoodFellas (1990)