'assurer' originates from Old French, specifically the word 'asseurer', where 'a-' (from Latin 'ad-') meant 'to' and 'seurer' (from Latin 'securus') meant 'secure/safe'.

'assurer' changed from Old French 'asseurer' and Middle English 'assuren' and eventually became the modern English noun 'assurer'.

Initially, it meant 'to make secure or guarantee', but over time it evolved into its current noun sense of 'a person who gives assurance' and occasionally 'insurer'.