Why?

I'm pretty sure I know why she's here. I'm just not sure why she doesn't open up more. She says all is well at home. Everybody's attitudes have changed (for the better I assume) including hers. As she puts it:
"I'm dealing without the highs. I'm fine with it, because with every high there are lows. And they were getting pretty low."
I was actually surprised to read this. I didn't expect that kind of honesty. Not since everything else she's wrote appears to be so distant. Yesterday I asked her to call me when she got the chance. Her reply:
"Thank you. (Sincerely) But I think I'll pass".
Today she tells me it took her 3 or 4 attempts to write that email. She was concerned how I would take it. I told her I would hope one of those ways would come from her heart.

So why is she here? I think its because she needs to be reassured I'm still here and have all the same emotions for her. That I still love her. That I still want her. But she wants to keep her distance. That's why she won't share the same emotions. I'm guessing she feels hearing my voice will crumble her wall. But I would bet anything that if I were to pick a time and place - she'd be there. But if I were to let my insecurities out, I would wonder if she's just not here to reassure herself that she can move on without me. That I've lost the ability to tear down her wall. Unfortunately for her, I see that as a challenge.