affiance

 
Pronunciation: /əˈfʌɪəns/

verb

(be affianced) literary
  • be engaged to marry: Edward was affianced to Lady Eleanor Butler (as adjective affianced) an affianced couple

Origin:

late 15th century: from Old French afiancer, from afier 'promise, entrust', from medieval Latin affidare 'declare on oath', from ad- 'towards' + fides 'trust'