The correct answer is - The romantic ideal of the pure maiden inspires the hero to begin his quest.
The protagonist is inspired by his crush, Mangan's sister, to set off on a journey to the bazaar in order to get her a present. She is his muse, his inspiration, someone he wants to woo and make happy by giving her a present from the bazaar. She doesn't help him in any way - she is just there to inspire him to 'great deeds' which he ultimately fails to accomplish.