Honestly, in order to believe it more, I would say that you would have better luck in dream. Maybe next time you find a story and LD, you find a nen eraser and have him destroy the vow. Or have him extend the vow to being on a scale of 1-10 how you liked the book, and that is the amount of days it is effective. Changing your mind in dream should be able yo effect you on a subconscious level (if you let it and have enough dream control).

Also, instead of doing vows and limitations check out something like Hukif's "clockwork" in order to change your ideas about things. I have my own, but until further notice, it doesn't work as well.

Secondary option is creating a fake memory. Sit down in a dark quiet room and pretty much LDD about the event. Add as much detail to it as possible to make it seem more and more like it actually happened and it should stick as a memory that is contradictory to the other one.

Or! Check out H. P Lovecraft, Edgar Allen Poe, or other short story beasts out there. a short story a day keeps Cthulu away! H. P. Also has tons of dream stories.