In the first moment of the embrace, Jekyll smiles, arms finding Dorian's back in return. But the strange thing is, after that moment, any happiness is suddenly gone, as if melted away. And yet it is still the same otherwise. It's very odd, and he doesn't feel sadness in its place, only...indifference. But that can't be right. He knows how he would normally feel, and did only a second before, so why should that change? He isn't unhappy. Everything else tells him he should be very glad right now.

So he fakes it. "Thank you, that's very reassuring."