In a medium sauce pan, combine water and sugar. Bring to a simmer over medium heat, stirring often. Cook until sugar has dissolved completely.
Add sage leaves and simmer for 1 minute. Remove from heat and allow leaves to steep for 30 minutes to 1 hour. (Depending on how strong you want the infusion to be.) Remove the leaves.
Transfer the cooled syrup to an airtight container. I like using mason jars for this. Store in the fridge for up to 3 weeks.