How we cite our quotes: Citations follow this format: (Chapter.Paragraph)
Quote #4
[Daniel] had learned to hate secrecy about the grand ties and obligations of his life—to hate it the more because a strong spell of interwoven sensibilities hindered him from breaking such secrecy. Deronda had made a vow to himself that—since the truths which disgrace mortals are not all of their own making—the truth should never be made a disgrace to another by his act. (19.4)
Secrets have played a major part in Daniel's own tribulations. When he meets Mirah, he realizes that she's someone who is also living with a secret identity – that is, she's hiding from her dad. He recognizes her as someone who is in the same boat, and he vows not to hurt her by betraying her secrets.
Quote #5
[Gwendolen] had burnt Lydia Glasher's letter with an instantaneous terror lest other eyes should see it, and had tenaciously concealed from Grandcourt that there was any other cause of her violent hysterics than the excitement and fatigue of the day: she had been urged into an implied falsehood. (35.125)
Gwendolen is also controlled by secrets – not only is she affected by Grandcourt's secret family, but she is also stuck with keeping her knowledge a secret.
Quote #6
That scene was now like an accusing apparition: she dreaded that Grandcourt should know of it—so far out of her sight now was that possibility she had once satisfied herself with, of speaking to him about Mrs. Glasher and her children, and making them rich amends. Any endurance seemed easier than the mortal humiliation of confessing that she knew all before she married him, and in marrying him had broken her word. (35.126)
One reason why Gwendolen has to keep her knowledge of Lydia Glasher a secret is that it seems kind of ridiculous, but also damnable, that she knew what she was getting into when she married Grandcourt but went through with it anyway.