German phrase
Ich bin mit ~ nicht einverstanden.
Meaning
I don't agree with ___
When to use it
It shows disagreement. Use it to politely oppose someone's idea or proposal.
Example dialogue
Ich bin mit deiner Idee nicht einverstanden.
I don't agree with your idea.
Warum nicht? Was stört dich daran?
Why not? What bothers you about it?