What significance does the grandmother's reference to "a good man" have in these lines from "A Good Man is Hard to Find" by Flannery O'Connor?

"Bailey Boy!" the grandmother called in a tragic voice but she found she was looking at The Misfit squatting on the ground in front of her. "I just know you're a good man, she said desperately. You're not a bit common!
The grandmother retains her belief in the goodness of people to the end.
The grandmother applies the term "good man" with no consideration of its meaning.
The grandmother hopes to convert The Misfit into a good man through religion

Question

What significance does the grandmother's reference to "a good man" have in these lines from "A Good Man is Hard to Find" by Flannery O'Connor? 

"Bailey Boy!" the grandmother called in a tragic voice but she found she was looking at The Misfit squatting on the ground in front of her. "I just know you're a good man, she said desperately. You're not a bit common!
The grandmother retains her belief in the goodness of people to the end.
The grandmother applies the term "good man" with no consideration of its meaning.
The grandmother hopes to convert The Misfit into a good man through religion