In the village where you see the man with four bottles, talk to him, and he will give you bottles.

Go to the long house where the man talks about his daughter. Exit the house, go to the other side, and enter. It appear that you can do so, but you can.

After you have obtained the flippers, cross the bridge and go down. Keep going until you see somewhere that you can enter. Then, swim under the bridge and talk to the man.

To get the fourth bottle, Go to where smithy would be in the Dark World. Sooner or later, a blue chest will appear. Bring the chest to the ex-thief by the desert in the Light World. He will ask if you will keep it a secret. Answer "Yes" and he will open the chest.

To acquire the bottle in the Dark World, use your Magic Hammer to pound the pegs that block you from your house east of the Village Of Outcast, then touch the locked chest inside. It will follow you. Go outside and use your Magic Mirror to the Light World. Lead the chest to the anonymous man (with the sign). You will find out that he is a lock-picking thief.

To get the final bottle, go to the blacksmith in the Dark World. There will be a chest here that you cannot open. Link will take it with him. Take it to the man near the desert, sitting next to the sign in the Light World. He will open it and give you the bottle inside.