'affirm' originates from Latin, specifically the word 'affirmare,' where 'ad-' meant 'to' and 'firmare' meant 'make firm.'

'affirmare' transformed into the Old French word 'affirmer,' and eventually became the modern English word 'affirm' through Middle English.

Initially, it meant 'to make firm or strengthen,' but over time it evolved into its current meaning of 'to assert positively.'