Where does “ensureth” come from?

ensureth (English) comes from English ensure, from Middle English ensuren, from Anglo-Norman enseurer.

ensureth (English): third-person singular simple present indicative...

Definitions

  1. third-person singular simple present indicative...

Ancestry of “ensureth”, step by step

ensureth traces back through two separate lines of ancestry.

via English ensure

StepLanguageWordMeaning
1EnglishensureTo make sure or certain of something (usually some future event or condition)
2Middle Englishensuren
3Anglo-Normanenseurer

via English eth

StepLanguageWordMeaning
1EnglishethA letter introduced into Old English to...
Every word from Anglo-Norman enseurerEvery word from Middle English ensurenEvery word from English ensure