From Longman Dictionary of Contemporary Englishbe betrothed to somebodybe betrothed to somebody old-fashionedSSFMARRYto have promised to marry someone → betrothed
Examples from the Corpus
be betrothed to somebody• His youngest son John was to be betrothed to the Count's daughter and heiress presumptive.• But she was being absurd, she scarcely knew this man and what was it to her who he was betrothed to? 