" Truth wealth is of the heart, not of the purse. " 

 Og Mandino
What i think this means is that in this case its not talking of wealth in literal, it is talking about who you are. Truth wealth is the kind of person you know you are. Money or wealth does not define you. Wealth is not what is in your purse there a meaning more beyond than that. I think wealth is what people know you for. It's how you are and what you show to people. It's pride and dignity.