An Eagle stayed his flight and entreated a Lion to make an alliance
with him to their mutual advantage. The Lion replied, "I have no
objection, but you must excuse me for requiring you to find surety
for your good faith, for how can I trust anyone as a friend who is
able to fly away from his bargain whenever he pleases?"
Try before you trust.
(Translated by George Fyler Townsend, 1814-1900)