That is a tough question to answer because there are no contemporary portraits of her, it seems that they were all detroyed. The National Portrait Gallery is the famous Anne Boleyn portrait yet, although the facial features may be correct, the colouring is wrong - Anne is described as having dark hair and "black eyes" not chestnut hair and light coloured eyes. The Hever Castle rose portrait is definitely closer to that description.
We have been discussing this very question on the forum - see http://www.theanneboleynfiles.com/forum/anne-boleyn-forum/what-do-you-think-anne-really-looked-like/ - and many people feel that the British Library Holbein sketch is probably the closest to what Anne looked like - see http://www.britannica.com/EBchecked/topic-art/269121/21695/Anne-Boleyn-drawing-by-Hans-Holbein-the-Younger-1534-35.
I think Anne Boleyn's exact appearance will always be a mystery so it is hard to know which portrait is more accurate. All we can do is look at contemporary descriptions of her and see if portraits match. By the way, Elizabeth I had a miniature of Anne Boleyn in her locket ring - see http://theanneboleynfiles.wetpaint.com/photo/5080059/Anne+Boleyn+and+Elizabeth - and I assume that the miniature would have been pretty accurate as there were people in Elizabeth's reign who would have known Anne and what she looked like.