The French thought that the United States seemed to like Great Britain better than France, even though the United States said that they were neutral.
Americans are neutral!
We are going to capture your ships!
The French were angry at the United Sates and Great Britain, so France started seizing American ships that traded with Britain.
The Quasi War ended with the signing of the Treaty of Mortefontaine. The United Statesand France signed this treaty which stated that captured ships would be returned to the U.S. and all previous agreemonts would be terminated.
By the end of the Quasi War, nothing was really accomplished.