'assent' originates from Latin, specifically the word 'assentire', where 'ad-' meant 'to/toward' and 'sentire' meant 'to feel, perceive'.

'assent' changed from Latin 'assentire' into Old French/medieval Latin forms (e.g. Old French 'assentir'), passed into Middle English as 'assenten'/'assent', and eventually became the modern English word 'assent'.

Initially it meant 'to feel toward' or 'to express agreement', and over time it evolved into the modern sense of 'to agree or express approval'.