Bring a pot of water to a boil and add the sago pearls. Stir occasionally to prevent sticking. Let them cook for about 10-15 minutes or until they turn translucent. Once cooked, drain and rinse them under cold water to remove excess starch. Set aside.

In a blender, combine half of the diced mangoes with coconut milk, evaporated milk, condensed milk, water, and vanilla extract. Blend until smooth and creamy. Adjust sweetness by adding more condensed milk if needed.

In a mixing bowl, combine the cooked sago pearls with the blended mango mixture. Stir well to evenly distribute the pearls. Fold in the remaining diced mangoes for added texture.

Refrigerate the Mango Sago for at least an hour before serving. This allows the flavors to meld and enhances the refreshing taste. Serve chilled with ice cubes if desired.