er weiß, was

he knows what

→ er
phrase Rare #23,906
he knows what Introduces an indirect question or subordinate clause. The verb in the following clause usually comes at the end, as in “Er weiß, was richtig ist” (“He knows what is right”).
GE: Er weiß, was er will.
EN: He knows what he wants.

Nicht mal er weiß, was er fangen wird.

Not even he knows what he will catch.

— The Wailing: Die Besessenen (2016)

Er weiß, was er will.

He knows what he wants.

Er weiß, was er an ihr hat.

He knows what he has in her.

Er weiß, was richtig ist.

He knows what is right.

— Der Untergang (2004)

Ich wollte, dass er weiß, was für ein Mensch sein Vater ist.

I wanted him to know what kind of person his father is.

— Der Fluch der goldenen Blume (2006)

Stimmt, und nur er weiß, was das mit einem macht.

That's right, and only he knows what that does to you.

— The Rip (2026)

Er weiß, was das bedeutet.

He knows what that means.

Er weiß, was man tun muss.

He knows what needs to be done.

— Leben! (1994)

Ich möchte, dass er weiß, was ich weiß.

I want him to know what I know.

— Kill Bill: The Whole Bloody Affair (2011)

Er weiß, was er sagt.

He knows what he’s talking about.

— GoodFellas (1990)

Er weiß, was vor sich geht.

He knows what's going on.