Add watermelon cubes, water, lemon juice and monk fruit sweetener to blender. Blend on high 1-2 minutes, until fully blended.
Pour mixture through fine mesh sieve to remove watermelon pulp. Pour strained watermelon lemonade into large glass jar or pitcher with lid. Refrigerate until ready to serve.
Serve watermelon lemonade over ice. Separation will naturally occur. Stir before serving.
Recipe by Sarah Bakes Gluten Free at https://www.sarahbakesgfree.com/2017/07/fresh-watermelon-lemonade.html