The question, obviously, of which fairy tale (or tale type) to rip off.
On the one hand, it obviously has to resonate with the tale, reflecting theme, plot, or even characters. "The Boy Who Set Out To Learn What Fear Is" is as inapplicable to a romance as "Cinderella" would be to a military adventure. But even there, the Boy does learn what fear is in the end -- after various characters have tried to teach him, the princess he married pulls it off. A prudent Love Interest could manage to parallel that for a headstrong main character. And if there is a romance subplot, perhaps it is with a downtrodden woman, living an onerous life because of the war about her -- though even there, I think "Catskin" or any of the semi-Cinderella variants where she runs away and gets a job as a scullery maid might work better. . . .
Which ties it in to the other hand, that you do not want it to reflect instead of resonating. Making it too obvious is ham-handed. The best stories in which characters are aware of other stories are those in which the characters make obvious comparisons both true and false between their lives and the stories they hear -- like Harriet Vane's reflections on her mystery, with half a dozen characters confined to her house, not conforming to the reality she just experienced where hundreds of women running all about had made it hard to determine even the suspects, or the way Daphne Tercius's stories and their genre are as much romantized as accurate, and she even complains once about a plot device that it's just a story, to have Harrier observe that the villain must have read it too. (unless you're being comic about it. All rules are off then.)
Which brings it back to the reading. A massive supply of fairy tales gives you a chance to find a suitable one.