Disney Syndrome is the development of a flawed out look on life. Little girls think there's true love and a "happily ever after" for all of them. That and their outlook on love is molded into an idea that love is romance and a hot, strong guy that will sweep them off their feet is what romance is (and thus what love is). While in fact none of these things are true.
Brittanie got hit with Disney Syndrome hard when her boyfriend didn't act like the prince she thought he would be.