In a saucepan, add the tamarind along with half a liter of water. Boil for 15 minutes till the tamarind softens.
Strain through a seive pressing down as much as liquid as possible.
Now add the tamarind again into the saucepan, with the remaining water and sugar and boil again for fifteen minutes. This is just to ensure to take maximum pulp off.
Strain into the previously prepared mixture. Discard the remains.
Mix in the rose water. Chill till use.
To serve, add 1/4 cup to 1/2 cup of the concoction to a tall glass. Top with ice and more cold water. Sweeten to taste, preferably with sugar syrup and enjoy immediately.