This happens usually when we try to be good to someone without any obvious reason or context.
As human beings, we live in a selfish world. So when someone tries to be good to us without any obvious reasons or context, we suspect his motives.
Thus misunderstanding happens. And person who may have extended his hands to help us, withdraws.
The solution is in belief that : There are many good natured people in world who help us on their own without any selfish motives.
If we accept such belief, it possible for to open ourselves to help from many unknown good people.