I couldn't agree more.
B2I completely agree with you.
Exactly!
B2I completely agree.
I'm of the same opinion.
B2My opinion is identical to yours.
You're right.
B2I acknowledge the correctness of your statement.
I beg to differ.
B2I respectfully disagree.
I'm not so sure.
B2I have doubts.
I disagree.
B2I have a different opinion.
I have my reservations.
B2I have some doubts or concerns.
I'm not convinced.
B2I'm not persuaded by your argument.
That's not quite right.
B2Your statement is partially incorrect.
I'm not entirely sure about that.
B2I'm hesitant to agree completely.
I think otherwise.
B2I hold a different opinion.
On the contrary...
B2In contrast to what you said...
That's debatable.
B2That point is open to discussion or disagreement.
I'd argue that...
B2I would claim or assert that...
I would contend that...
B2I would maintain or assert that...
However...
B2Nevertheless, despite that...
In contrast...
B2On the other hand...
Nevertheless...
B2In spite of that...
Nonetheless...
B2Despite that...
Notwithstanding...
B2In spite of; despite...
To the contrary...
B2In direct opposition to that...
I'm inclined to agree.
C1I tend to agree, but not completely certain.
That's a valid point.
C1I acknowledge the merit of your argument.