晩婚: late marriage / 盤根: intertwined roots

a reason / a motive

to select; to choose / to elect / to screen

explanation

to explain

late marriage

Kyūjitai form of 今晩: (time) this evening, tonight

he / distal demonstrative, something far off removed from both speaker and listener: that / boyfriend

distal demonstrative, something far off removed from both speaker and listener: that, yon / particularly, male personal third person pronoun: he / by extension from he: boyfriend

he; boyfriend