"我对他的话半信半疑“求助这句话的英文翻译

我对他的话半信半疑
1.I'm not certain about what he said.
2.I dounted/wondered what he said.
3.I am uncertain about what he said.
4.I am doubtful about what he said.
5.Wheather his saying true or not is a mistery.
其中,what he said可以改成his saying.

I'm uncertain what he said.

I'm uncertain about his words.

I am dubious of his words.

I told him of hearing