The word "dude" is usually for men, and "darling" is usually for women. But "dude" can be casual and neutral friendly, but "darling" implies a loving relationship. They are not equal.

maybe you should give a specific scenario.. I always prefer my darling of course. but to some extent (outdoor activities, big boy's talk, etc.), I prefer my dude. :)

Neither, I like to call a person by their own name.

I think boys used word 'dude' mostly for boyfriends,while 'darling' word is used for girlfriends for wives.But i don't know about girls that which word they use.

I prefer word "darling".