You can comfortably do this on the second island, when you reach the city of Orad. There are plenty of monsters lurking around the City and in the Hopper Forest. When you are exploring the areas and doing the side quests, the 200 cumulative pearls are easily and quickly achievable. Just simply don't spend the these pearls for upgrading your stats. At this stage, your main character should be strong enough to survive these battles without this few round of upgrading.
The real difficulty here is to spot this trophy in the list rather than fulfill the requirement. :)