There are three levels of certainty that you can have when making a claim (that is incorrect, as there are of course millions, but anyway these are the three basic ones):
1) Know = I believe it to be so, like really really totally a lot okay? Just trust me okay?
2) Believe = I think it's true and ain't no one gonna tell me otherwise Jack!
3) LOLWUT = Considering that I could be wrong, and that others could be wrong, I am left with LOLWUT
So then, "LOLWUT" is closest to truth/reality, and "know" is furthest from it.