Question

Which sentences in this excerpt from W. W. Jacobs's "The Monkey's Paw" show that the White family does not believe in the talisman’s power? The other shook his head and examined his possession closely. "How do you do it?" he inquired. "Hold it up in your right hand, and wish aloud," said the Sergeant-Major, "But I warn you of the consequences." "Sounds like the 'Arabian Nights,'" said Mrs. White, as she rose and began to set the supper. "Don't you think you might wish for four pairs of hands for me." Her husband drew the talisman from his pocket, and all three burst into laughter as the Sergeant-Major, with a look of alarm on his face, caught him by the arm. "If you must wish," he said gruffly, "Wish for something sensible." Mr. White dropped it back in his pocket, and placing chairs, motioned his friend to the table. In the business of supper the talisman was partly forgotten, and afterward the three sat listening in an enthralled fashion to a second installment of the soldier's adventures in India.

Answer 1

"Don't you think you might wish four pairs of hands for me"

Answer 2

I think the correct answer to your question would be:

"Sounds like the 'Arabian Nights,'" said Mrs. White, as she rose and began to set the supper. "Don't you think you might wish for four pairs of hands for me."

and

Her husband drew the talisman from his pocket, and all three burst into laughter as the Sergeant-Major, with a look of alarm on his face, caught him by the arm. 

In these parts it shows that they use sarcasm and also laugh at Sergeant-Major.

Hope I've helped!