Why Do Strawberries That Are Sprinkled With Sugar Make Juice?

This happens by the process of osmosis.
Strawberries have a high water content, so their contents are dilute. Sugar crystals contain no water, but sugar is hydrophilic in nature so the presence of sugar on the outside of strawberry membrane draws the water from the cells out into the sugar. This will slowly continue until the watery solutions in and out of the cell match each other in concentration.