Combine the cranberries, juice, water, and sugar in a pot and bring to a boil. Turn the heat down to a simmer for 15-20 minutes until thickened. Placing a wooden spoon over the pot can help the mixture not bubble over.
Taste and adjust the sugar level to your liking. I prefer mine more tart so 1/3 cup is perfect. My mom prefers it sweeter, closer to 1/2 cup of sugar. Store in the fridge or serve warm.
Notes
You can make this refined sugar free by adding maple syrup or honey instead of sugar (or really any sugar substitute you like).
I like POM brand of pomegranate cherry juice, but you can use all tart cherry juice or all pomegranate juice.
For a southwestern flair, add 1 small chopped jalapeño that's been deseeded.