Board Thread:Speculation House/@comment-27603392-20130223042647/@comment-5607322-20130227124903

I think can fits better into the theme of loneliness than can't; If she is keeping it hidden from others then she is alone in whatever burden it brings her; but can't makes it sound like she tried to hide it, but failed. And if her friends are aware of it then they indirectly share the burden by accepting Weiss in spite of it.

This is going off the idea that she blames herself for what happened, which would explain why she wants to keep it hidden from others and also fit with the lines "Fear of whats inside of me; tell me can a heart be turned to stone?"

This also works in in logistics of character development - RWBY finds out Weiss has terrible secret in her past. Weiss gets depressed about it (maybe tries to leave). RWBY solves some issue about it. Everyone accepts Weiss despite knowing what she did. Weiss is happy knowing they don't blame her. Everyone is happy and eats ice-cream and does backflips THE END

Supporting your hope it may be a typo is that the lyrics Jeff posted was "Fear of whats inside of me" but Casey seems to sing "Fear of whats inside me"