Actually, her level 4 limit break is quite easy to get. Since you have to use your x/1 limit break a certain amount of times in battle, just manipulate a monster, and have it attack her, and since her limts are all curative, she can use her limit as many times as you want in 1 battle. then just have her kill all the enemies. Only took me about 40 minutes to level her up to limti 3/3. then after that it was cake getting the mythril to the guy.