saiba o que fazer

know what to do

→ saber
phrase Rare #32,702
know what to do Used after verbs like esperar or querer to express uncertainty or hope about someone's ability to act.
PO: Espero que você saiba o que fazer.
EN: I hope you know what to do.

Talvez ele não saiba o que fazer!

Maybe he doesn't know what to do!

— A História sem Fim (1984)

Eu quero ter certeza que o Tom saiba o que fazer.

I want to make sure Tom knows what to do.

Tom espera que Mary saiba o que fazer.

Tom hopes Mary knows what to do.

Quero ter certeza que o Tom saiba o que fazer.

I want to make sure Tom knows what to do.

Espero que o Tom saiba o que fazer.

I hope Tom knows what to do.

Eu espero que Tom saiba o que fazer.

I hope Tom knows what to do.

Talvez o Tom não saiba o que fazer.

Maybe Tom doesn't know what to do.