Broke no contact after another suicide threat. What should I tell her?

Today she posted on her blog that she was going to skip the part where she survives a suicide attempt. It was just the latest threat but the most serious sounding so far

I couldn't take it anymore and messaged her

Quick backstory. She discarded me about 3 months ago. She likely has BPD and NPD. BPD people have a 10% suicide rate.

A couple weeks ago she unblocked me after posting continuous suicide threats on her blog for over a month.

I messaged her if she is okay. She said yes and asked how I was. I messaged her that I still care about her, and I always will. I also asked if she wants to talk about anything. She said that she misses me. I told her we'll talk and it tomorrow

Our 10 month relationship​ was very unstable. I don't want her back, because I know she'll repeat everything. Unless she gets serious psychiatric help she will burn every relationship she is in to the ground.

It's a shame because she's intelligent, creative, funny, and beautiful.

I just don't know what to tell her. She is very suicidal, but there's no way I can take her back. How do I give her the bad news without making her harm herself?