Secret Diaries of Miss Miranda Cheever Julia Quinn

At the age of ten, Miranda Cheever showed no signs of Great Beauty. And even at ten, Miranda learned to accept the expectations society held for her--until the afternoon when Nigel Bevelstoke, the handsome and dashing Viscount Turner, solemnly kissed her hand and promised her that one day she would grow into herself, that one day she would be as beautiful as she already was smart. And even at ten, Miranda knew she would love him forever. Author of Bridgerton