Look at the model hair and her right shoulder, thats where the light come from, should be direct sunlight. That means the sun is on the model back right hand side. The window glass also act as a diffuser so the sun light is not so harsh.
Also look at the model eyes, there is no catch light, that means the photographer did not use a flash or reflector. He most likely take the light reading directly from the model face, thats why you can see the model face is exposed well, but the background is over-exposed / wash-out.