betrothed
be·trothed
I
 /bıˈtroʊðd/  adj  
   formal + old-fashioned   : engaged to be married
   a betrothed couple
   She had been betrothed to the prince since she was a young girl.
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II
  noun   [  singular  ]
   formal + old-fashioned   : the person that someone has promised to marry
   He spent the afternoon with his betrothed. [=fiancée]