I thought; was supposed to
Suponía que podía ser peligroso, pero en ese momento no lo pensé.
I assumed it could be dangerous, but at the time, I didn't think about it.
— Mujeres al borde de un ataque de nervios (1988)
Suponía que eras canadiense.
I assumed you were Canadian.
Sí, suponía que lo haría.
Yes, I assumed he would.
— Rebeca (1940)
Yo suponía que sería usado como un libro.
I assumed it would be used as a book.