不确信英语怎么说

I'm not sure if you look nice in this shirt .

I'm not sure / certain if / whether this shirt looks good / nice on you.I'm not sure of / about whether this shirt looks good / nice on you

I am not sure if it works.

翻译：I am not sure that.希望能帮助到您，谢谢。

我不确信:I don't think so,I don't know 我确信:I believe 去那儿玩:where should we go for a play? 去那里玩:We'll go there for a play