Rinse the fresh cranberries thoroughly, removing any that float to the surface. Peel and chop the ripe Fuyu persimmons into small chunks for even cooking.

In a medium saucepan, mix together the cranberries, persimmons, granulated sugar, freshly squeezed orange juice, and water. Stir well to combine all the ingredients.

Bring the mixture to a gentle boil over medium heat. Stir occasionally until the cranberries begin to pop and break down, about 5-7 minutes.

Reduce the heat to low and let the sauce simmer for about 15 minutes, stirring occasionally until it thickens to your desired consistency.

In the last few minutes of cooking, stir in the ground cinnamon to enhance the flavor.

Remove the saucepan from heat and allow the sauce to cool for about 10 minutes. Transfer it to a serving dish where it can be enjoyed warm or chilled.