You don't get them to stop. You just ignore it. It'll eventually play itself out. No, you should not care. You just continue to be the best YOU you can be, and the truth will shine through. Yes, if people you know believe her, you should kick them to the curb too.

Being the bigger person, without people KNOWING you're being the bigger person is in itself a challenge. You don't want that to be misinterpreted as spineless or a sign of low self esteem, however in the end people thinking that is in my opinion worse then you proving yourself and not only showing that it bothers you, but actually letting it bother you. I agree with koolman, you wont be able to get them to stop, nor will they if you and do something about it, it will only fuel their fire and they will succeed in their intentions of bringing you down to their level.

In the end you will understand what it truly means to be the bigger person by experiencing this struggle, and you will be a better person for it. Each experience, good or bad is an opportunity for growth.

So, how do you do it. Ignore it, when people are letting you know of what she says about you, say "I'm not interested in hearing about that. I'm not interested in the drama people try and create and want to be at peace. I am only interested in hearing about those I love and want to attract moments that enrich my life, not try and tear it down. Thank you for your concern in trying to keep me in the loop, but it's a poison I could do without. So tell me, what's new with you?".

Good luck

I like that Rosebud!

I was going to ask... WHO is telling you that you are being badmouthed? Cause I would ask myself why is this person telling me that I am being slandered??

Are they truly trying to help you and give you a heads up so you can protect yourself??

Could they be trying to cause trouble because they want you to be on the outs with certain people?

It is so scary that people can and do spread poison and gossip around.. trying to manipulate how others view each other, isn't it?
That is a really bad trait of human nature and soooo evil
I think we have to trust that motives WILL come to light and anyone worth having as a friend makes up their own mind about people and would never go on what a third party says.. I know a lady who tried to manipulate me by telling me bad things about others... I didn't believe what she was telling me.. but I kicked her to the curb pretty fast because ..." If they'll gossip TO you.. they'll gossip ABOUT you"
Just make sure you're don't dealing with a double crosser

Ignore it.

I like Koolmans answer.

Vmarshall

There is a group on DS for victims of sociopaths/psychopaths/narcissists, they may be able to give you more insight on how to deal with this.

http://www.dailystrength.org/groups/victims-of-psychopaths-sociopaths

Eventually, people running their mouths about someone, but that someone (you) not responding or fanning the flames, only makes them look stupid. I mean, if people talk shit, and five years from now they still are, but in the mean time, you have moved on, lived your life, become a ghost...THEY look ridiculous, not you.

My ex MIL and SIL talked so much crap about me while I was married. They even "joked" about my X doing the woman I, eventually, found out he was cheating with. When I confirmed it, I sent my ex MIL and SIL a text saying, "Hey, ________ is fu**ing ____, just like you thought. You were right! Good job and have a great day!" Of course, they backpedaled because their mouth-running caght up with them and, strangely enough, Not ONE nasty word was said about me as we went through our separation and divorce.

I was the one who shut down communication with them because I no longer had to "play the game" now that we were divorced. When I go to NY visit my family, and that is also where my x MIL is, I am cordial and polite because of my son..but there is nothing NOT artificial about our "relationship" now.

My point is, people will talk crap. Some are so bored, or so unhappy with their own lives, they have to talk about others because, if they took a moment to look inward, they wouldn't like what they see.

Be better than that. Move on, keep not baiting them...you will come out on top.