In the second-to-last paragraph, Mrs. Hopewell sees Manley in the distance and assumes he's been selling Bibles to black people who live in woods nearby. This kind of completes the persistent idea of blindness running through the story—Mrs. Hopewell sees Manley coming from her property, and knows Hulga and Manley were seen together the day before, but she still thinks of Hulga "as a child" (2) and can't imagine her with Manley or any other man. She sees, but doesn't have enough imagination to put things together.
On the other hand, there's a good chance that Mrs. Freeman does put things together. Check out how she closes the story:
Mrs. Freeman’s gaze drove forward and just touched him before he disappeared under the hill. Then she returned her attention to the evil-smelling onion shoot she was lifting from the ground. “Some can’t be that simple,” she said. “I know I never could.” (144)
Her gaze "touches" him—she sees him clearly, for who and what and how he is. There is something familiar or tangible about him to her. And while at first glance it might seem her comment about simplicity is in regards to Manley, like she is subtly saying Manley's not as simple as he seems, it can also be understood as a little jab at Mrs. Hopewell. Since Mrs. Freeman doesn't specify who is simple, it's possible she's referring to her boss, at least when it comes to the activities of her own daughter on her own property.
It's a pretty open ending. So what do you think?