Castaway Paradise

All of the mobile Villagers (Viktoria, Gustave, Amelia, Angus, Francis, and Stevie) will have an unlimited number of quests available to do. When you talk to them, select to get a new quest from them. You can only carry 3 at a time and there is no way to drop them so when you pick one up, thus you are stuck with it until it's complete. You can check your progress for this trophy in the Start Menu - Trophies - Second tab. The trophy tile will be grayed out, but will slowly fill with color as your progress towards 100.

As soon as you complete and turn in your 100th quest, the trophy will unlock.