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you mean it require berserk charge ability?There are 2 methods I used to obtain easy 99 hits.
First is to equip Berserk and Air Side Slash (not sure on the English term, but the 3rd in your ability list), and unequip all MP Hastes. Enter battle and use Cure. Jump, attack and press square till you reach 99 hits.
Second method is to equip Rumbling Rose, all Finish Pluses, and Combo Minus. Unequip all Combo Pluses. Enter Wisdom form then battle. Spam attack till you finish your first long combo, you should reach 48-51 hits. Pause for just a second till it slowed down its spin for a little, and start your second combo for 99 hits.
First method is the easiest but require Berserk, which is end-game (Keyblade) and/or level 85 (Shield). Second method is much faster (around 15 secs to get 99) but needs practice on the timing between the 2 combos.