In social circles how do you get rid of a foe?
Well... one way as an example:
You tell someone a story about someone else. The story has to be emotionally provocative and result in either disdain or superior indifference. It can be entirely contrived.
"Do you see that guy over there? I know him. We were members of the same country club. Beautiful wife. Two kids. Everyone thought they were so happy. (play it up) Well, one day his wife came home and saw him slapping around the maid as she was on her knees fellating him."
Now. It does not matter if you actually know that person. Nor does it matter if you just met the person you are telling it to. However, that person will absolutely despise that man AND protect her social circle from involving themselves in any way. They will never verify it.
And for the bonus, she will trust you as her confidant to always tell her the truth.