Polly (Edwardian Candlelight #1)
Jennie Tremaine, Marion Chesney, M.C. Beaton

Pretty Polly Marsh just didn't know her place. But others did...and were only too happy to remind her that dashing Lord Peter was merely playing when he seemed to be paying her court. The duchess was beside herself. Peter's brother, the starchy Marquis of Wollerton, was desperate to pry Peter from Polly's side. But Polly was determined to have Peter -- and her dream. He wouldn't betray her now... would he?