[Hayame does not actually know what she asks of him. She imagines the shards to be... akin to holding a man's heart somehow in your hand, that their body would not die as long as the shard was intact. She had not conceptualized that, if they could be removed safely from the body for spells and Communion, that there would somehow be a limit to how far they could be taken away from the body, or that it would render the body without sense or powers. (Because surely... the shards weren't them, they were just some strange magic tool...)

But he refuses. Of course he does. To have hoped for that trust was disgustingly foolish of her, when she should have known this was likely all a trap and she would need to shoot him through the eye and take the shard by force. Once she got it back to Greensblood... she could oversee more magical persons attempt to cleanse the black sludge out.

His offer of his god's book might sound permissible as a substitute, except last time she had heard...]

What use for swearing upon is a sacred book to a man who claims his god's grace has left him?

[She stands taller, towering over him with a growing pressure fueled by doubts and suspicion, bitterness over her failure to convert the one person she has owed enough to try.]

Or do you claim to believe in it once more?