How do we know our take on the universe is any better than anyone else?
We don't, in any ultimate sense.
But we can take our views for a gallop on RF and see how many times we get knocked over. That will give some indication, though an indication under very particular circumstances.
I attempt to solve that one by my three assumptions. (They have to be assumptions because I can't begin to demonstrate their correctness without having first assumed they're correct.)
That a world exists external to the self.
That the senses are capable of sufficiently informing the self about that world.
That reason is a valid tool.
Those who post on RF thereby demonstrate that they already share the first two assumptions, and I hope they share the third.
So in my view, on the basis of those assumptions, we know because there's a world external to the self, our senses can sufficiently inform us about it, and we can validly use reason to find out about it.
That external world is objective reality. As for 'truth', a statement is true if it accurately reflects / corresponds to / conforms with, objective reality.
Should we be more empathetic towards those who view life differently from ourselves? If so, how?
At the dinner table, in the bar, in public, we should endeavor to maximize respect between people, stay away from unnecessary argument, and be good friends and citizens.
On RF, well, if we don't argue, we'll never learn, and worse, we'll never have any fun.