Ending good enough?

Hi, everyone.

Could you tell me what type of ending is the author talking about?

Does she mean by the phrase in bold that the story ENDs with a dumb innocent person outwiting us?

"Oh, Pa, this is a simple story about a smart woman who came to N.Y. C. full of
interest love trust excitement very up to date, and about her son, what a hard time she had
in this world. Married or not, it's of small consequence."
"It is of great consequence," he said.
"O.K.," I said.
"O.K. O.K. yourself," he said, "but listen. I believe you that she's good-looking, but I
don't think she was so smart."
"That's true," I said. "Actually that's the trouble with stories. People start out fantastic, you think they're extraordinary, but it turns out as the work goes along, they're just average with a good education. Sometimes the other way around, the person's a kind of
dumb innocent, but he outwits you and you can't even think of an ending good enough."
"What do you do then?" he asked. He had been a doctor for a couple of decades and then an artist for a couple of decades and he's still interested in details, craft, technique.
"Well, you just have to let the story lie around till some agreement can be reached between you and the stubborn hero."

Coud you tell me what the last line means as well. I would be grateful.

Source; A conversation with my father by Grace Paley.

Thanks!