The Mysterious Maid-Servant by Barbara Cartland

Have you ever been so desperate that you would do literally anything for money? This is the tragic situation Giselda finds herself in, with no money for an operation her younger brother desperately needs to save his life, and no one to turn to. Ground down by poverty she plucks up her courage to offer the only thing she has of value – her purity.
Choking back her pride and knowing that she is about to forfeit his respect, she approaches her wealthy employer, the handsome Earl of Lyndhurst, who is recovering from his injuries sustained in the Battle of Waterloo.
Appalled that this frail and innocent young girl should be faced with such a terrible decision, he vows to find a way to help her without offending her dignity. He knows she would never accept his charity, and she refuses to confide in him the reasons for her family's poverty.
Intrigued by the air of mystery about a girl of obvious quality reduced to the role of maidservant, the Earl decides to discover why a beautiful young woman of strong principles has been reduced to such extreme measures.
Discovering her to have gentle hands and wonderful nursing skills he employs her as his private nurse and turns his sharp mind to uncovering her secrets – and learns his own lessons in love in the process.