From Longman Dictionary of Contemporary Englishbetrothalbe‧troth‧al /bɪˈtrəʊðəl $ -ˈtroʊ-/ noun [countable] old-fashioned SSFMARRYan agreement that two people will be married SYN engagement
Examples from the Corpus
betrothal• A spot on a collar can spoil a betrothal.• But betrothal began to wear on Margarett.• As for Richard's betrothal nothing came of it.• In February 1173 he met Humbert at Montferrat in the Auvergne to finalize the details of the betrothal.• So the betrothal was arranged and the marriage soon followed.• All at once Jehan realised that Jehana had not yet given her reasons for consenting to betrothal with Alexei.• Some initiation ceremony perhaps or unspoken betrothal? 