So in your example, ‘Il mio fidanzato si sposerebbe subito..’ the correct translation can be ‘would get married right away’ along with the ‘si’ is made use of because in Italian it’s a reflexive verb. in https://majaoozo663429.oneworldwiki.com/6121039/the_smart_trick_of_can_you_learn_italian_in_a_year_that_nobody_is_discussing