une fois pour toutes
Meanings
Adverb
1. once and for all (finally, permanently, conclusively) (idiomatic)
Examples14
You've got to give up gambling once and for all.
Make up your mind once and for all.
Turn him down once and for all.
Get it settled once and for all.
I will repeat it for you once and for all.
They have solved the problem once and for all.