Add the 1 cup of pineapple juice, 1 cup of water, and 4 tbsp of agave nectar into a sauce pan and bring to a boil. Then, turn the heat down to low and stir for 2 minutes. Then, transfer to a container.
Add the 1 cup of basil leaves and allow to steep for about 10 minutes. Then, drain the liquid through a strainer removing any solids such as the basil leaves.