Final answer:
Shelby's description of Tom is ironic because he trusts and admires Tom's moral character, yet still treats him as property to be sold to settle his debts, highlighting the hypocrisy of slaveholders during that time.
Step-by-step explanation:
The irony in Shelby's description of Tom in Uncle Tom's Cabin lies in the fact that Shelby, a slaveholder, acknowledges Tom's exceptional trustworthiness and moral character, despite his own participation in the fundamentally immoral act of slavery. Shelby admits that he trusts Tom with significant financial responsibility and respects his Christianity and honesty, going so far as to let him travel alone with a large sum of money. However, this trust and recognition of Tom's character do not prevent Shelby from treating him as property to be sold in order to settle a debt. This underscores the hypocrisy and moral corruption that slavery fosters even among those who seem to recognize the humanity of their slaves.