The Actress and the Rake — Carola Dunn

Sir Barnabas's Will requires granddaughter Nerissa Wingate and godson Miles Courtenay to live together chastely in his house for six months in order to inherit his estate. He assumed they'll fail. Fuming but penniless, they accept the challenge, but a host of hopeful relatives is determined to throw them into each other's arms, and Sir Barnabas's cantankerous ghost lends a hand! Regency Romance by Carola Dunn: originally published by Zebra as The Lady and the Rake