Maria Antoinette was the duchess of Austria, until she married King Louis the XVI at age 14. They got married to form and alliance between Austria and France.
Maria was very vain and instead of spending time on the well-being of her country, she spent time on her own appearance. This meant that she spent a bunch of money on her own luxury instead of putting money into helping the country. The people of France didn't like her for this reason.
Maria and Louis had trouble conceiving a child, this lead to mockery from everyone around them. This was a hard time for both of them because people were saying if they can't produce an heir to the throne than how can they rule a country?