A person thinks he is prosperous because has millions in his bank account, another thinks he is prosperous because can pay his bills on the end of the month and manages to keep and infimum amount of his salary. Which one is right? That can't be determined because what matters is how the person feels. It is even possible that the person who has less feels more prosperous than the one who has much.
What if someone says that people are kind but another disagrees and says that people are cruel? Before answering who is saying the truth, consider this: the first one has received a kidney transplant from a mere acquainted, while the other one has been robbed, beaten and humiliated. Aren't they both telling the truth? Yes, because on the basis of their personal experiences that is true for them.
The "truth" is that the truth is a mental concept, non existent in the fisical world. What we consider to be truth is nothing more than a colective mental concept, that is, what we and the people of our culture around us consider to be truth. The truth varies according to the culture and period in history that we are examining.
But one thing I know to be true: today was a sunny day wasn't it?