比如， 某件事的确定性

I am a chinese, 确定性 refers to whether you are sure about something, you can contact me to help each other, because I want to learn English. My QQ is 89646597, looking forward your reply. What your QQ number?

A:你确定锁门了吗？ B:我确定我锁门了！/ 我不确定我是否锁门了。 如果你认真复习了，你一定能通过考试。 如果你没有认真复习，你不一定能通过考试。 A：你今天来我家玩吗？ B：一定来。/ 不一定来。 A：你确定今天来我家吗？ B：我确定。/ 我不确定。 Be sure there are no cars before you cross the road. 在你过马路前先确定没有车。 确定没有车了你再过马路。 世界杯比赛中有许多的不确定性。 法律是具有确定性的。. Its difficult to use 确定性 to make a sentence. Just as xutopia says, 不确定性 is normally used.

确定，和is relevant to “ sure” when used in a answer. It emphasizes your objective opinion。For example " Are you going to the club tonight?"你今天去夜店吗？ " I am not sure."我不确定“（ 确定 can also be your statement of certainty , for example " i am sure that i have locked my door last night" 我确定昨晚关了门。we won't say 我昨晚一定锁了门，（just sounds strange， while few people do use this） at this scenario 肯定 is interchangeable with 确定 for most times ，but ”一定“means “ must be。。” The water becomes ice when the temperature is below zero。。水在低于0度的气温下一定会变成冰。（ to express a fact）。and “不一定is more subjective to ”确定“ You will achieve a nice grade if you study hard， 只要你努力，你一定会取得很好的成绩"确定性" is hardly used in daily Chinese. More often, it expresses the "uncertainty" " We can not forecast earthquake accurately because of its uncertainty" 因为地震的不确定性，我们不能准确地预测。。。In short 肯定or 确定can be used in all tenses， while 一定， usually used in present and future tense。 I agrees with 伊丽莎白‘s opinion ， 不一定 can also be translated to “ who knows” while 不确定can only be “ not sure with”。

My understanding is that 不确定 is an adj more like uncertain , I was told to say 不一定 as a verb Im not sure 不一定。 Really interesting question I will be checking this again i wonder what the excat difference is!