Kim does seem to use the "B" word and other not so nice words as terms of endearment at times. Maybe it would have simply been better if someone would have told her that they don't care to be called these things in any context.
Sweetie seems to be as much of a PITA as Kim. What happened to the woman that she had last season who watched over her daughters? The girls seemed to be sad that Sweetie was leaving, but the other woman seems far more responsible. Kim went to her to tell her youngest that she couldn't have soda. Maybe the girls like Sweetie because they get away with more when she is around. I don't know if the other woman was an "assistant" like Sweetie or just a nanny for the girls.