What does Charles Darnay tell the Doctor on the morning of his marriage to Lucie?

Before Darnay begins his courtship of Lucie, he asks her father for permission to pursue his daughter. He tries to tell Dr. Manette his true identity at that time, and to explain why he had fled France and changed his name, but Dr. Manette is insistent that he not do so until the morning of his wedding to Lucie, if things should so work out (Book the Second, Chapter 10)....Although it is not directly stated, the reader gets the sense that Dr. Manette has known all along that Charles Darnay is a decendant of the dreaded Evremondes...In other words, Dr. Manette knows that Darnay is an Evremonde, but he also knows that Darnay does not share in the family's notoriety, neither in action nor in spirit. For his daughter's sake, he makes the supreme effort to not let Darnay's ancestry stand in the way of their courtship and eventual union.