'assuror' originates from Middle French, specifically the word 'assureur', where 'assurer' meant 'to make sure, to secure'.

'assuror' changed from Old French 'asseurer' and ultimately from Latin components (see below); the modern English noun developed via Middle French 'assureur' and Early Modern English borrowings to become 'assuror'.

Initially it related to the action 'to make secure' or 'to ensure'; over time it evolved to refer to a person or entity who provides assurance or insurance: 'one who guarantees or underwrites'.