Maiden of Mayfair (Tales of London #1) by Lawana Blackwell

An orphanage in the slums of London is the only home Sarah Matthews has ever known. When she is suddenly whisked away to a wealthy widow's home in the prestigious Mayfair district, Sarah can't fathom what has happened. Why would this elderly woman, a stranger, want her company? But Dorothea Blake has reasons she isn't revealing. As Sarah blossoms into a young woman, the secret Mrs. Blake harbors threatens to make them both outcasts among London's elite. When a visitor unknowingly stumbles upon the truth, he puts Sarah at risk of losing everything she holds dear, including the attentions of a new curate. Will the mystery of her birth remain buried forever?