The USS Assurance was an Ambassador-class Federation Starfleet starship in service in the 2350s and the 2360s. The Assurance was commanded by Captain George Walter and had a crew of around seven hundred.
In 2362, the Assurance was on patrol near Tzenkethi space with the USS Okinawa. When the Okinawa detected valuable bilitrium deposits on several planets in the Entelior star system, the Assurance joined with the other starship to stop the Tzenkethi from seizing the deposits. During a battle with the Tzenkethi near Entelior IV, the Assurance was rammed by a Tzenkethi marauder and was severely damaged, causing it to become caught in the gravity of the planet. In a plan devised by Benjamin Sisko, three shuttlecraft from the Okinawa, the Chatan, the Nago and the Naha, were connected to the Assurance by the tractor beams that was emitted by the starship in an attempt to pull the Assurance out of the planetary atmosphere. The shuttlecraft Nago was destroyed in the attempt, but the Assurance, its velocity slowed by the success of Sisko's plan, crashed onto the surface of Entelior IV with minimal casualties. However, the Assurance was invaded by the Tzenkethi soon after and its crew captured and brought aboard a Tzenkethi starship. The crew were tortured by the Tzenkethi for information and just eleven survivors, including Sisko and Walter, were rescued from the Tzenkethi by the Okinawa. (ST - Typhon Pact novel: Rough Beasts of Empire)