Paine's past is a mystery since she will never talk about it. It appears that she, Nooj, Barelai, and Gippal shared that past. A lot of this past is recorded into something called Crimson Spheres. Here's where you get them.

1: recieved after you've followed Gippal under the Bevelle Underground.
2: recieved from Nooj after you've defeated Ixion in the Farplane.
3: recieved from Gippal after you've defeated Ixion in the Farplane.
4: recieved after you've found it in LeBlanc's room.
5: recieved from LeBlanc in the airship's engine room after the 1000 words FMV.
6: recieved in the middle of the room in Bevelle Underground's 100th floor.
7: recieved from Nooj in Mushroom Rock.
8: recieved after you've defeated a fiend in Bevelle Underground's 20th floor.
9: recieved after you've found it on the Mushroom Rock Road.
10: recieved after you've found it in one of LeBlanc's rooms.