German phrase
Ich habe starke Vorbehalte gegen ~.
Meaning
I have strong reservations about ___
When to use it
It shows strong concern. It is fairly formal and can sound firm in discussion.
Example dialogue
Ich habe starke Vorbehalte gegen diesen Vorschlag.
I have strong reservations about this proposal.
Warum? Was stört dich daran?
Why? What bothers you about it?