Need help with a girl online

I’ve been talking to This girl online for the past year and it has been really amazing especially the past few months were incredible. We’re not a relationship couple but we’re more then friends and even had talks or marriage and dating one day. And randomly she pulled away a few weeks ago. After doing research on her behaviour im 90% sure she has avoidant attachment and I know I’m an anxious. She’s also going through a really really bad deprsssive episode and she says she doesn’t feel like herself and she’s overwhelmed and exhausted all the time. How do I get the old her back that used to wanna date me and marry me. How do I prove to her that I’ll never ever leave her and I won’t hurt her like how her exs did in the past. Cuz before she said I’m the only guy I trust to date and now she doesn’t want me. I really really need her back I’ll do anything