How do I tell a co worker that they’re being rude in a workplace friendly way?

Long story short, I trained this girl. I am one step above her since I am the head preceptor. I have been at this job almost two years. Management is aware of our strained relationship and it at least seems like they’re working on something behind the scenes. But for now all I can do is play the waiting game. This co worker regularly sends very passive aggressive emails to the whole team which are clearly directed at me because she can’t poke holes in my actual performance (my recent review went very well) But I am about to pull my hair out over these emails and her passive aggressiveness in general. How do I tell her in a workplace friendly way that I don’t appreciate her attitude when interacting with me? I have tried to grin and bear it but I just cannot anymore.