Final answer:
Madame Forestier was astonished when she met Matilda ten years later because Matilda had borrowed and lost her necklace, only to find out it was fake after years of hard work to repay the cost.
Step-by-step explanation:
Madame Forestier was astonished when she met Matilda ten years later because Matilda had borrowed and lost a necklace from Madame Forestier, believing it to be valuable. However, after ten years of hard work to repay the cost of the lost necklace, Matilda discovered that the necklace was actually a fake and worth very little. Madame Forestier was surprised by Matilda's determination and sacrifice, as she had assumed Matilda was rich and still in possession of the expensive necklace.
Learn more about Madame Forestier