deep + cry... focus on the CRY PART ...a girl CRYING to express her disapproval of getting married now.
De+ cry= kids cry when they want to show disapproval.
de + 'cry'...any one will cry to show their disapproval
decry-> girls deep cry for the disapproval of marriage by loving boys
decry is crying and weeping but with a "de" which means deep disapproval