Combine sugar, water, and chopped apples in a pot over medium heat.
Stir until sugar dissolves and the liquid turns clear (about 5-7 minutes).
Remove from heat and stir in the passionfruit pulp.
Let steep for 30 minutes to infuse the flavors.
Strain through a fine-mesh sieve (or cheesecloth for a clearer syrup).
Bottle and refrigerate - lasts up to 2 weeks.