Well, let’s imagine a negative plot. Maybe she is a lure to get the man of the house outside while her boyfriend gets in the house. I think most of us would be leery of opening the door for her. I would call the cops quickly and pray that they would be quick. The delay tells her that cops are being called and she disappears.
We just had one of those in a really good neighborhood here in town. Woman rings the doorbell, someone cracks the door, woman asked if they had a gas can, and then 2 thugs in hoodies with guns come around the corner, crash through the door and hold the people in the home hostage while they steal everything they want. All caught on a Ring doorbell.
Motto: never open your door to a stranger even if it is a woman.