The Assurance is an icebreaker docked at Stormwind Harbor. It was set to sail to Northrend, but they noticed a severe number of "bugs" aboard. The crewmates of the ship are all named after members of the Testing and QA teams for the Burning Crusade.
The ship is most likely named The Assurance in reference to Quality Assurance, as the crew are named after members of the Testing and Quality Assurance teams for the Burning Crusade.
The ship may also be named after Crimson Permanent Assurance, the financial "ship" from the opening sketch of the film "Monty Python's The Meaning of Life".