What does it mean for girls to call boys good husbands?

Calling a girl a boy is a pet nickname for men, representing intimacy.

When a girl calls a boy dear, it means that she has regarded him as her boyfriend. She likes this boy, and she calls him that in order to enhance their feelings.

"Darling" is a kind of "special address", which is generally owned by close people. However, between the opposite sex, "special address" often represents ambiguous or definite relationship, and similar addresses include "baby", "baby" and "pig".