On the package of devil's food cake mix, there should be directions for preparing your cupcakes. The only difference is that you are going to replace a quarter cup of the water normally used with rose water. You may adjust the amount of rose water according to preference, but the total water content of both should stay at 1 1/4 cups.
For the frosting, in a bowl, combine butter and sugar. Beat till blended.
Add the cream, rose water, vanilla and food coloring and beat for an additional 3 to 5 minutes or until smooth and creamy.