The Hoyden and the Rake by Victoria Price

Strong-willed, and independent debutante Fiona, flees home to avoid the unwanted advances of her suitor. Her attempt to escape is foiled when an accident forces her to take shelter in the home of her brother’s sworn enemy and notorious rake, Phillip, the Earl of Sheffield. Shunned by the ton for his dark past, Phillip is a reluctant host to the impetuous young lady who turns his orderly world upside down. Sparks fly despite their resolve, but the norms of regency society and Phillip’s reputation forces them apart. Will Fiona and Phillip defeat the odds and find each other?