Large diffused source (might even be natural) from near directly behind her turned way down if artificial. Look at the shadow of the flower on tha back of her neck just above the dress line. To me that shows the direction of the light.
I am then going to say that the her face is ambient. As for the background, I am not sure.... It could be getting enough off the diffusion source. to be lit like that --- notice the fall off right to left. Perhaps the background is dodged a bit and the face burned a bit too.
Those who know more than me will hop in and correct me, I am sure......
I'm going with two lights and some post work on the shadows.
One light for the background to evenly light it. A large softbox behind and just in forward of the model feathered for the edge of the light falling on her.
I see post work to modify the shadows in the hair. The hairband maintains a constant exposure value even as it's being surrounded by shadows on both sides along the top. The front of the hair along the back bump falls into shadow quickly while the back of the front bump that is practically touching it is unaffected even as it curves back, they should both have fall off as they recede.
The front of the face also looks to have had the shadow enhanced for effect.