In Chapter III of the Second Book of A Tale of Two Cities, after Charles Darnay is arrested for being a spy, testimony reveals that Lucie Manette spoke with Darnay on a boat going from Calais, France, to Dover, England. Miss Manette describes Darnay as "kind, good, and useful to her father." "I may not repay him by doing him harm to-day." In spite of her good intentions, however, she naively testifies that Darnay had told her his was an assumed name; he was hiding his real name because of the nature of his mission. Of course, when Lucie's testimony casts aspersions upon Darnay's character, she is distraught because she did not intend to harm him. Unfortunately, she further implicates him as a sympathizer in the American Revolution against King George III. Yet despite this damaging testimony, when she looks upon Darnay "with such pity, and such earnest youth and beauty" it is "very trying" to Charles Darnay. Then, in Chapter IV, after he is acquitted thanks to the genius of Sydney Carton, Mr. Darnay kisses Lucie's hand "fervently and gratefully" for the kind words about him that she has said, suggesting that Darnay has strong feelings about Lucie.
Further, Chapter X of the Second Book begins with a description of Charles Darnay, who has established himself as a tutor in the year after his trial. Dickens writes,
Now, from the days when it was always summer in Eden, to these days when it is mostly winter in fallen latitudes, the world of a man has invariably gone one way--Charles Darnay's way--the way of the love of a woman.
He had loved Lucie Manette from the hour of his despair. He had never heard a sound so sweet and dear as the sound of her caompassionate voice; he had never seen a face so tenderly beautiful....
So, because he loves Lucie and because the secret of his family is connected to Dr. Manette, Darnay pays the physician a visit. Once there, he begs of Dr. Manette that he will "urge no influence against me" as long as they both agree to their conditions. Darnay asks Dr. Manette for permission to court Lucie.
Certainly, the affection that Lucie has for Darnay have been apparent in the courtroom. This affection hints at, or foreshadows, her marriage to Charles Darnay. Of course, that Darnay receives permission to court Lucie from Dr. Manette is more evident foreshadowing.