Go to South Hyrule Field on the bottom left side. Equip your sword and the Pegasus Boots. Run into the sparkling bush and it will turn into a stump. You must have learned the dash attack from Swiftblade to do this. Become small and go into the Minish house. Fuse Kinstones with the Minish there. Visit Syrup the witch in the Minish Woods. She will now stock Red Potions for 150 rupees. This will replenish all of you hearts.