Hi there!
This always seems to be labeled as paparazzi style shot taken while she was unaware, but looking at them closely & it's obvious they are posed shots.
Everything around the model is plainly set up, look at all the pretty items around the scene.
Body type should also be a
big clue.
As
ballyhoo points out, Audrey Hepburn was very thin & the woman in the photos has a fuller "pin-up" style figure.
There's a series of these,
including the above discussed image, by
Andre de Dienes, here's some of the same model with the same hairstyle but showing her face, clearly not Audrey Hepburn.
Compare the bath tub taps & they match the tub in the supposed Audrey shot.
Think it all adds up to being convincing proof these are not Audrey Hepburn.
Hope this is of use!