I mean, it is weird, is it not? Things were going exactly as she describes, so she did hold expectations for it to continue so. She is no doubt a special existence, a heroine, holding an oracle of the world in her head. And has received validation of how special she is for the entire time both before and after she enters the story. The only things that did not go as the prediction said is that the less important capture targets rejected her, which she accepted with only a little bit of whining (after a large bit of not realizing it). So she could clearly grasp that they are individuals not bound by fate, and was not so selfish she tried to force it self-rightously.
But for what reason was she given an oracle if not to capture the capture-target of paramount importance? And her dropping the phrase "fated one" should make the prince understand what she is referring to (and thus pick her), considering what he said in the end of the game/oracle. It would be unthinkable for it to have just been romantic babble!
I don't remember which chapter that quote you used comes from btw. But as you quoted it in a spoiler I assume its from a future one when she finds out the birds fate? Which only serves to make her outburst even more understandable, the outcome is the absolute worst and completely disproportionate to what a saint trying to save the world expects.
...Though I remembered her reaction as being more subdued than that. But it makes more sense that my memory is off than the context of your quote, as it was a while I read it.