I'll never... be able to... prove that until... I'm fully dead...

[He says that with a huff and wry tone that's partially ruined by his rasping. He's going to thank Faust regardless and Faust knows it.

The rest renders him quieter. Part of him wants to insist that it's not enough, but he's also touched that Faust would think otherwise. It's the final comment that outright throws him. He looks up, blinking.]

You... really think that...? I would've... I would've thought...

[He trails off.]