Saved by the Scoundrel by Rose Pearson

Although she never thought of herself as one of the lucky ones, Caroline Devonshire’s life could have been in a much dire state than it was at the age of 18.
Orphaned when young, her older brother managed to secure her a home under the watchful eye of the widowed tavern owner, Mrs. Beeson, before setting off for war in France.
And while her brother’s absence would prove to be a trial, Caroline managed to survive and thrive in her less than ideal surroundings.
Although she tries to keep foolish dreams in check, Caroline secretly hopes to live an adventurous life beyond the Smithfield Market, beyond London, and even beyond England. That is, until her brother, Peter, finally returns home for good and shows himself to have become the type of rogue that a life of adventure can breed.

Worse still is Peter’s companion, a certain Lord Timothy Brandeis, who though cherishing a strong and special bond with Caroline’s brother through the war, is also partially responsible for her brother’s current standing as a scoundrel and a rogue.
Even though this handsome and charming man proves to be little better than the louts Caroline deals with every day, she finds it hard to not look his way in a manner that doesn’t escape the eyes of Ms. Beeson.
Things become even more complex when Lord Bradeis’ duties as the second son of a Marquis force him to make an appearance at his family home and Caroline is shocked to find that this roguish Lord has a rather adventurous request to make of her.
Soon she’ll need to collect all her wits to manage in a realm her active imagination had never dared to take her: the world of le bon ton in Regency Era England.