I'm not too sure if this is right.

这是否正确，我没有太大把握。

《牛津词典》

I'm not too sure of it.

这件事我不太有把握。

youdao

I'm not too sure about the writing here.

我不太确定这部分文字。

youdao

Make sure the soil is not too wet or the seeds could develop poorly.

VOA: special.2009.03.24

I'm not too sure. I think that there's loads of different art colleges,

我不能确定。我想这儿有很多不同的艺术学院，

伦敦的时尚学院 - SpeakingMax英语口语达人

It decreases. If you're still not completely up on the periodic trends, that is stuff that's going to be on the first exam, so make sure that you're able to do this without taking too much time to think about it.

它会降低，如果你还没有完全掌握周期性规律，而这是第一次考试要求的内容，因此请务必做到不用,想太久就能做到这点。

麻省理工公开课 - 化学原理课程节选

I'm not too sure if Brother Bill is going to be some baggage or not.

NPR: Virginia Democrats Eager for Primary, Election

Even creditors are now none too sure about the worth of the ministry's guarantee.

ECONOMIST: And it finally came to tears

But the methodology and sample size are such that you can't be too sure of the Scottish figure.

BBC: No longer the poor relation