Examples
实话说,我不赞成你。
To tell the truth, I don't agree with you.
Frankly speaking, I don't agree with you.
Source: Tatoeba
我完全不赞成你的意见。
I do not agree with you at all.
Source: Tatoeba
很抱歉那个问题我不赞成你。
I'm sorry I don't agree with you on that matter.
Source: Tatoeba