In The Necklace, what does Loisel suggest to make Mathilde agree to go to the party?

Mathilde
has always thought herself destined for better things. She has this strange notion that she has
aristocratic blood coursing through her veins. This makes it all the more difficult to deal with
her current status as the wife of a lowly civil servant.

Monsieur Loisel is
acutely aware of his wife's frustrations and does everything he can to please her. When he comes
home from work one day with an invitation to the Education Ministry ball, he assumes that
Mathilde will be tickled pink at such an opportunity to rub shoulders with the social
elite.

But Mathilde is far from pleased. She has absolutely nothing to wear;
she's ashamed at the size of her wardrobe and doesn't want to be the poor relation at the
Education Ministry ball. Eager as always to please, Monsieur Loisel offers to buy Mathilde a new
dress for the princely sum of 400 francs. But even that's not enough. Mathilde moans that she
has no jewelry to wear. It's then that her husband makes the fateful suggestion that she should
go to her friend Madame Forestier and ask her if she can borrow some of her
jewels.