troth-plight

n. act of plighting or pledging troth,sol-emn promise of marriage. betrothal保证忠诚，庄严许婚，订婚。
～ p. a. formally betrothed (which in Elizabethan dayswas almost as binding as being married) 正式订婚的。
△H.V. 2. 1. 19 (17): “It is certain,corporal,that heis married to Nell Quickly; and certainly she did youwrong,for you were troth-plight to her.”千真万确，伍长，他已经和耐尔·桂格莱结婚了；她也真对不起你，因为你跟她订过婚约。