In a small saucepan, set on high heat, bring the water and sugar to a boil, stirring constantly. Remove from the heat and add the cilantro.
Set aside and allow to steep for 15-20 minutes. Drain through a fine sieve and toss the leaves. If the syrup still feels warm, pop it into the fridge or freezer for a few minutes. Otherwise, proceed to the next step.
Add the cilantro syrup, mango, lime juice, coconut milk and salt to a blender. Puree until smooth (about 60 seconds). Pour into the bowl of an ice cream maker and churn according to the manufacture’s manual.
Once you have finished churning the sherbet, transfer the mixture to a loaf pan. Use a spatula to smooth the mixture out, then cover with plastic wrap (press the wrap down so it’s completely touching and covering the surface of the sherbet).
Place the pan in the freezer until the mixture is solidly frozen, at least 2 hours. Scoop and serve.
Transfer leftovers (if you manage to actually have any) to an airtight container and store in the freezer.