What would you do if you heard someone insult you behind your back and say all kinds of vicious things?

If you encounter someone who speaks ill of you behind your back, or even very unpleasant words, then you must first stay calm, because there may be such people at any time, even if you No matter how well you do, some people will say something bad about you, because you can't take into account everyone's interests and everyone can't be satisfied with you. So it's normal for such people to exist, but how should we deal with it? As for this kind of thing, first of all, if it does not have a substantial impact on you, you can ignore him for the time being, but if it does, you must take measures to dispel the other party's arrogance.