I didn’t get that either.. I went back and read it but maybe she was alluding that someone close to her has died before (but not from her past life, I don’t remember there being anyone like that) or that she’s almost died before (from the assassination attempt)
It's the bad translation, she was probably just referring to the previous assassination attempts done on her and Ysis.
Remember Edenverre tried to poison both Aisha and Ysis when they were younger? Marianne was talking about that.
Wait, she didn't know it was Alyssa ? Then why did she say "you already know death" ?