German phrase
Unverhandelbar ist ~.
Meaning
___ is non-negotiable
When to use it
It states a firm boundary. It signals that a principle or decision will not be changed.
Example dialogue
Kannst du nicht noch einmal darüber nachdenken?
Can't you think it over one more time?
Unverhandelbar ist meine Entscheidung.
My decision is non-negotiable.