[He smiles, too, if only out of sympathy for what she's saying]
Yes. I can imagine it's so. [Not like he doesn't know himself, yes, cough]
I'm unsure if she'd wish to be open with me, but I can at the very least encourage her to be open with you. She relies on you a great deal and always speaks of you kindly, Constance. I'm sure that she keeps something from you because she believes it's for the best. [And not because she doesn't trust you]