1. He calls his wife "sweetheart."
2. He calls his wife "Sweetheart."
3. He calls his wife Sweetheart.
-------------------------------
Are they all grammatical? Which ones are correct?
================================
4. She begged one more chance of her.
5. She begged her one more chance.
(Is #4 the same as #5? Are both grammatical?)
#1 is correct; 2 an 3 aren't.
I'd use #4, but #5 is not correct unless you insert "for" after "her."