“It’s not the truth. It’s what I believe to me the truth.” Huh? Here we are distinguishing between the truth and what one believes to be the truth. OK, people have a hard time telling the difference. To compare the truth with a belief about the truth is like comparing a painting of a landscape with the actual landscape. Even to most accurate painting is going to have some variation. On top of that, the canvas is just not big enough to include the entire landscape. A belief is the canvas for which the person paints their estimation of the landscape of truth. It will never be 100% accurate, but it gives us somewhere to roam, otherwise we only will roam within our immediate surroundings.
On a simple level, I have to believe that there is a roadway, a bridge and that my car is in the driveway before I will attempt to go out the front door and drive to another City. Those beliefs are based on my experience of reality. However I have not experienced everything. On each journey, I will add more to those beliefs. Each time expanding the beliefs a fraction of an inch closer to reality.
I must be humble to know by beliefs will never 100% be the truth about reality. And, one piece of new information may change everything.