Once Upon A Mattress (2005) on Netflix

Plot summary

Prince Dauntless cannot marry until Queen Aggravain approves a bride, and none of the princesses brought before him has met her standards. Dauntless tells his mother he believes she is sabotaging his prospects, and she denies it. Lady Larken discovers that she is pregnant, and she and Sir Harry, who commands the kingdom's guard, cannot wed until the prince does; if he stays single, Larken will be banished. Harry goes searching and returns with Winnifred, who comes from the swamps in the north and swims the castle moat to get there. Aggravain finds her disgusting, but Dauntless loves her at once and persuades his mother to give her a chance. While the court ladies help Winnifred dry off, Aggravain and the Wizard pick a test of sensitivity: a single pea under twenty mattresses, to be laid that evening.