Alas, Receiver, this Bearer is unable to oblige you; for reasons beyond their control, they cannot hope to go along with your wishes. Since such obstacles are frequently matters of religion, creed or some similarly sensitive subject, and thus insurmountable, it is recommended that the Receiver not push for an answer as to why the arrangement cannot go ahead in greater detail.
However, should such clarity be desired, then
Tell me more or
Tell me the truth may be sent, although Bearers are advised to bear in mind the possible consequences of such unmediated honesty before doing so.
More sensible, perhaps, would be to respond with a graceful
Fair enough,
Of course or
I understand. If challenge is required,
I dare you provides it;
Trust me assures their concerns are groundless, while
Hold your horses gently suggests a misunderstanding has occurred and
Big mistake robustly declares the Bearer has made an error.