I´m afraid I have to disagree.
I disagree completely.
I´m sorry to say I´m not entirely convinced.
I don´t agree at all.
I just don´t agree.
I don´t really agree.
I don´t completely agree.
I agree up to a point, but not fully.
I´m afraid I don´t quite agree.
I feel I must disagree.
I´m not convinced.
I see your point, but I don´t really agree.
I totally disagree.
I can´t really say I agree.
I am entirely in disagreement.
