"I want nothing from you." I like it too, if framed in a way that Tav has no thoughts of any "reward" in mind. Tav is just happy because everything worked out, happy that Astarion is now finally free, he won't have problems with hunger and sun, he has power, etc. That's the reward.
For example, " My love, you said you feel alive again? I don't need anything more than that."
And a variant: "Nothing? Oh my dear, then you simply must (with dark undertones) allow me to bestow a gift upon you." Would be a great answer to that.
