First of all, Pour the water into the pot and let it to boiling temperature. Then, lower the flame and add sugar to the pot. Stir the mixture to dissolve well.
Once the mixture is well dissolved, add the saffron and rosewater to the solution. Now your syrup is ready, put it on the flame for 10 minutes to thicken.
Remove the pot from the heat and allow it to cool. Then pour it into a container and put it in the refrigerator.
Your saffron syrup is ready to use. Whenever you want to use it, mix a quarter glass of syrup with cold water and drink.
Notes
These ingredients are enough for a family. Be careful about sugar amount and don't overdo it. About saffron, first, grind saffron threads, then brew it and use. This is the most efficient application.