Not going to argue how beautiful she is because she is. I question how natural she is though. Truly natural would mean no make up of any kind. She's wearing eye make up and her brows have been shaped (tweezed). I will give you that comparatively speaking to many of the photos of women posted here, she is much more natural looking than most. I like that her freckles show.
Compared to the impasto that passes for makeup and the photoshops that pass for photography today, this picture is as close to natural as you're likely to see, unless you are bedding this girl. To say nothing of the tweezing her eyebrows bit... come on.
I don't know who this girl is. But this picture really highlights her beauty. Maybe it's an illusion - maybe it's the perfect angle, the perfect lighting, the perfect makeup, the perfect hair, the perfect retouching, the perfect everything really. But even if it is an illusion, I can tell you honestly: if you asked me to define beauty,
this is what I would have in mind.