99.9% sure: 99.9% is absolutely rock-solid; a person who says they are 99.9% sure of something is presenting insight with undoubtable knowledge of the topic. This information can be counted on.
99.99% sure: 99.99% is still measurably accurate. Usually, 99.99% is reserved for situations in which there still remains room for unexpected events. This information can still be counted on, but watch out.
99.999% sure: 99.999% represents the beginning of a slippery slope of doubt. 99.999% generally is used for opinions or statements that cannot be backed with empirical evidence. Most people who frequently express political beliefs will say they are 99.999% sure of something. Be careful before believing someone who is 99.999% of something.
99.9999% sure: At this point, we cannot be completely sure of how positive someone is of something. If a person says they are 99.9999% sure of something, it is basically a 50/50 situation.
99.99999% sure: If a person says they are 99.99999% sure of something, they genuinely have no fucking clue what they are talking about.
Connor: I am 99.9% sure that the sun will rise tomorrow.
Daniel: I am 99.99% sure that the next Battlefield game will be kickass.
Evan: I am 99.999% sure that Dirk is a homosexual.
Dirk: I am 99.9999% sure that Evan has been raped in the shower.
Johnny: I am 99.99999% positive that Socialism will prevail.
Rebecca: I am 99.999999% certain that I was a cow yesterday and will be again tomorrow.