Fra The Age of Innocence af Edith Wharton:

"[...]"Very handsome," she added, returning the jewel; "very liberal. In my time a cameo set in pearls was thought sufficient. But it's the hand that sets off the ring, isn't it, my dear Mr. Archer?" and she waved one of her tiny hands, with small pointed nails and rolls of aged fat encircling the wrist like ivory bracelets. "Mine was modelled in Rome by the great Ferrigiani. You should have May's done: no doubt he'll have it done, my child. Her hand is large--it's these modern sports that spread the joints--but the skin is white[...]"

Definition på 'set off':
bring out: direct attention to, as if by means of contrast; "This dress accentuates your nice figure!"

Hun er mener sarkastisk, at en nok så smuk ring ikke hjælper en grim hånd...

Det hjælper med noget kontekst...