Because "A Rose for Emily" is narrated with shifts in time by possibly more than one third-person narrator, there is a certain ambiguity that serves to create the stunning and horrifying ending. Three elements of ambiguity are as follows:
1. What may have occurred with the visit of the minister to Emily.
Because of their disapproval of Emily's association with the laborer and Northerner, Homer Barron, the ladies of the town force the Baptist minister to make a visit to Emily in Part IV.
He would never divulge what happened in that interview, but he refused to go back again.
Then, the minister's wife writes to Emily's relations in Alabama, who visit Emily. After their visit, Miss Emily goes to the jewelers' and orders a man's grooming set in silver to be engraved. Two days later she purchases an outfit of men's clothing, including a nightshirt and the townspeople guess, "They are married."
Since Miss Emily has purchased the rat poison prior to the visit of the minister, his refusal to return to the Grierson house points to Emily's intentions of preventing Homer from leaving her. Apparently, then, she said something to the minister, or there was evidence in the house of something sinister that caused the man to be greatly disturbed.
2. The cause of the strange odor emanating from the Grierson house.
The evidence of Homer's death at the conclusion of the story confirms that Emily has poisoned him, and it has been his decaying body which has created the odor.
3. The resolution of what has happened to Homer Barron
After Emily's death, there is one room upstairs that "no one had seen in forty years." When Emily is in her grave, this room is forced open.
In this room the "man himself lay in the bed....rotted beneath what was left of the nightshirt...and upon the pillow beside him...in the second pillow was the indention of a head...[with] a long strand of iron-gray hair.
Now, the townspeople understand why Miss Emily made the purchase of the men's items herself.