Doing good could be very tiring in many ways. I know it from my experience.
I have helped people who pretended to be helpless. Moved with compassion, I shared my resources with them. Once I took the money that I kept for my children's school fees and pooled it with donations from other people to get a poor girl college education. She went to college but the first thing she bought was an expensive phone which most of her benefactors could not afford. She had the resources, it seems, for the college fees and also for the phone. We felt cheated.
It had happened to me many times in one form or other. Every time, when I discover that I was cheated, or I realize that my money ended up in something that was not genuine, the will to do another good ebbs away. It requires so much will power and optimism to believe that this time it will be okay.
But patience has its limits. Our moral stamina also reaches its boundaries. That is when Paul's advice to the churches in Galatia comes to strengthen us. Paul said, 'And let us not grow weary of doing good, for in due season we will reap, if we do not give up' (Gal 6:9, ESV).
First, we should keep doing good things in spite of frauds. Counterfeits should not make us believe that the genuine doesn't exist. Secondly, there will be some results anyway. Who expects all seeds to germinate and sprout? Will all eggs hatch into chicks? In spite of the potential failures, the peasant still sows and the farmer still hopes eggs to hatch.
Charity should be an untiring effort.