The motif Purification with water is a part of: Magic
Water, purification, magic, power
But the Princess was still a witch, and she had no love for John at all. His comrade kept this in mind, and gave him three feathers from the swan's wings, and a little bottle with a few drops of liquid in it. He said that John must put a large tub of water beside the Princess's bed, and just as she was about to get in bed he must give her a little push, so that she would tumble into the tub. There he must dip her three times, after he had thrown the feathers and the drops of liquid into the water. That would free her from the spell of sorcery, and make her love him dearly.
John did everything his companion had advised him to do, though the Princess shrieked as he dipped her into the water, and struggled as he held her in the shape of a large black swan with flashing eyes. The second time, she came out of the water as a swan entirely white except for a black ring around its neck. John prayed hard, and as he forced the bird under the water once more it changed into the beautiful Princess. She was fairer than ever, and she thanked him with tears in her beautiful eyes for having set her free from the sorcerer's spell.