Tough question and the simple answer is that we don't know for sure. All the portraits we have of Anne are supposedly copies of earlier portraits yet we have the National Portrait Gallery portrait showing her with chestnut coloured hair and light brown/hazel eyes and the Hever Castle portrait (the one with the rose) depicting her with very dark eyes and hair.
The poet Thomas Wyatt gave her the poetic name "Brunet" (Sir Thomas Wyatt, "Collected Poems") and Nicholas Sander (“The Rise and Growth of the Anglican Schism”) described her as having "black hair".
I personally think she looked like the Hever Castle rose portrait - dark brown hair and dark brown eyes, very different to the classic English Rose.
