You didn't, I did. You said it is a fixed belief. You said 2+2=4 is a belief, and some stuff about 2+2=5. Of course I believe 2+2=4, I don't think it is a belief, I think it is a fact.
Your last paragraph did not answer how anyone would know that a belief corresponds to the truth. As you say, some beliefs are reasonable, some are not, but that does not make that belief a truth.
That doesn't make sense.
I don't think it is a belief, I think it is a fact.
So now you don't think people believe facts?
Let's see if this helps:
define:belief
"any cognitive content held as true"