This character is an idealist, someone who is absorbed with living life the way they perceive it should be. They purposely overlook the darkness of human nature in favor of seeing everyone in an unrealistically good light. To an idealist, there are no such things as bad people. There are only bad situations people are in that force them to act a certain way. Finally, an idealist is someone who expects the best from people, not realizing that not everyone is willing to give up their time or money as willing as they are.
The opposite of a cynic, an idealist often has the nature of selflessness and believes in things like honor, justice, honesty, etc.