If someone is a pessimist,bad reputation,talks bad about others is trying to befriend you do you avoid / talk to them?

I feel like i should because she can be nice , but she has this mean girl side , and i hear its better to surround yourself with people you'd to rub off on you , my friends tell me not to

Talking is fine, most of the time when she's not bad mouthing others ,

You know what me too! , i feel a bit guilty but i don't need this drama either

I watch how people treat those they don't like, if they're actively hateful and vindictive that makes me nervous because I think: "what happens if WE fall out someday ?"