So for those who mention her personality difference between now and before : have you ever had your heart crushed when young?
I had my heart crushed many times, young and old and I can tell you : it shapes you into a different person.
According to some reviews she becomes her self when she's back with him : because her heart is restored.

I had my heart crushed forever and nothing will be restored. I'm a total different person.
When you lose a loved one, that's what it does.

I'm at episode 6 and enjoying it so far.