Ernestina refers to the civil offence of Breach of Promise. In this period, an offer of marriage from a man to a woman was considered a legally-binding contract and financial recompense could be sought if the man broke this contract.
Middle- and upper-class families rarely brought actions against the men who broke engagements with their daughters, because of the embarassment and scandal caused by the necessary courtroom examination of private affairs and documents. As this 1860 article on the problems of breach of promise cases observes:
"The court vastly enjoys the perusal of [the defendent's] letters, and the papers quote them entire and unabridged."