HMS Assurance was a 44-gun fifth-rate Roebuck-class ship of the Royal Navy launched in 1780. Commissioned in the same year, the ship served throughout the remainder of the American Revolutionary War on the North America Station. Her service there included capturing the American privateer Rattlesnake on 17 June 1781 and coordinating the evacuation of Savannah, Georgia, in July 1782. Having briefly served as a troop ship during the subsequent peace, Assurance was recommissioned in 1793 for the French Revolutionary Wars. Operating in the West Indies, she served in Sir John Jervis' fleet that captured Martinique, St Lucia, and Guadeloupe in March and April 1794, also playing a part in the capture of the French frigate Bienvenue on 17 March.

Assurance was given over to the Transport Board for use as a troop ship in 1796. With a stripped down armament she served in this capacity at first in the Mediterranean Sea and then returned again to the West Indies. Part of a convoy sailing from Martinique in 1798, Assurance assisted in saving the crew of the storm-stricken store ship HMS Etrusco on 25 August. The ship was then in ordinary at Woolwich Dockyard, serving as a receiving ship, between 1799 and 1815 at which point she was broken up.

Assurance was a 44-gun, 18-pounder Roebuck-class ship. The class was a revival of the design used to construct the fifth-rate HMS Roebuck in 1769, by Sir Thomas Slade. The ships, while classified as fifth-rates, were not frigates because they carried two gun decks, of which a frigate would have only one. Roebuck was designed as such to provide the extra firepower a ship of two decks could bring to warfare but with a much lower draught and smaller profile. From 1751 to 1776 only two ships of this type were built for the Royal Navy because it was felt that they were anachronistic, with the lower (and more heavily armed) deck of guns being so low as to be unusable in anything but the calmest of waters. In the 1750s the cruising role of the 44-gun two deck ship was taken over by new 32- and 36-gun frigates, leaving the type almost completely obsolete.

When the American Revolutionary War began in 1775 a need was found for heavily armed ships that could fight in the shallow coastal waters of North America, where two-decked third-rates could not safely sail, and so the Roebuck class of nineteen ships, alongside the similar Adventure class, was ordered to the specifications of the original ships to fill this need. The frigate classes that had overtaken the 44-gun ship as the preferred design for cruisers were at this point still mostly armed with 9- and 12-pounder guns, and it was expected that the class's heavier 18-pounders would provide them with an advantage over these vessels. Frigates with larger armaments would go on to be built by the Royal Navy later on in the American Revolutionary War, but these ships were very expensive and so Assurance and her brethren continued to be built as a cheaper alternative.

Ships of the class built after 1782 received an updated armament, replacing the small upper deck 9-pounder guns with more modern 12-pounders. Assurance, constructed before this, followed more closely to the 1769 armament of Roebuck and did not receive these changes. All ships laid down after the first four of the class, including Assurance, had the double level of stern windows Roebuck had been designed with removed and replaced with a single level of windows, moving the style of the ships closer to that of a true frigate.

All but one ship of the class were contracted out to civilian dockyards for construction, and the contract for Assurance was given to Randall & Co at Rotherhithe. The ship was ordered on 20 May 1778, laid down on 11 June the same year and launched on 20 April 1780 with the following dimensions: 140 feet 4 inches (42.8 m) along the gun deck, 115 feet 11+1⁄2 inches (35.3 m) at the keel, with a beam of 38 feet 2 inches (11.6 m) and a depth in the hold of 16 feet 4+1⁄2 inches (5.0 m). Her draught, which made the class so valued in the American Revolutionary War, was 10 feet 3 inches (3.1 m) forward and 14 feet 9 inches (4.5 m) aft. She measured 898 45⁄94 tons burthen. The fitting out process for Assurance was completed on 15 July at Deptford Dockyard where she also received her copper sheathing. Her construction and fitting out cost in total £20,922.

Assurance received an armament of twenty smoothbore 18-pounder long guns on her lower deck, with twenty-two 9-pounders on the upper deck. These were complemented by two 6-pounders on the forecastle; the quarterdeck was unarmed. The ship was to have a crew of 280 men, which was increased to 300 in 1783. Her name had been used by the Royal Navy since 1605.

Assurance was commissioned by Captain James Cumming in April 1780, while the ship was still being completed. She sailed on 27 October to join the North America Station. There, the ship captured the American privateer brig Duke of Leinster on 23 May 1781, and two days later took the schooner Fanny. Subsequently serving alongside the 24-gun frigate HMS Charlestown and 24-gun post-ship HMS Amphitrite, on 7 June the three ships came across the 16-gun ship-sloop HMS Atalanta in Boston Bay. Atalanta had been captured by an American frigate on 28 May and her prize crew was attempting to sail her into Boston. The British ships re-took Atalanta and sent her to Halifax, Nova Scotia.