Movies like The Little Mermaid

A retelling of the famous fairy tale by Danish writer Hans Christian Andersen, of the youngest mermaid princess who saves a human prince on their birthday, falls in love with him, yearns for his love and a human soul, and bargains her fish-tail for legs with the Sea Witch, sacrificing her beautiful voice as payment. (If this is going to be truthful towards the original story, do not expect a 'happy' ending!)