how can i get an awkward, near-suicidal married woman to leave me alone without her going into some depressive deathspiral

i just want to be friends with her, no more

TBH, telling her "leave me alone you stupid cunt" might just pose as a challenge for her...

as a female, just tell her that you are in no way interested and that you just want to be friends and if she can't accept that, then you want nothing to do with her. tell her bluntly. when it comes to stuff like that, you can't dick around and just try to soften the blow because you're worried she might hurt herself. there's no way to reject anyone who's unstable.