betrothed
noun [ S ] formal or old use uk/bɪˈtrəʊðd/ us/bɪˈtroʊðd/
未婚夫；未婚妻
a person that someone has promised to marry, or has been promised to as a marriage partner
He sent a dozen roses to his betrothed. 他给未婚妻送去一打玫瑰。
Compare: fiancéfiancée