how did the horses help the count to make madame villefort's acquaintance?

The Count wins the trust of Madame Heloise de Villefort. By "saving" her from the wild horses, and rejuvenating her son, Madame de Villefort is so impressed with the miraculous Count. He knows the story will be related to her husband who will feel obliged to visit the Count. This is how the Count schemes to meet his nemesis.