Within the castle of her facade, she keeps her heart hidden. Protected with her fragile body, not letting it fall on the wrong hands. For it was as fragile as glass, one wrong move can break it apart. But that heart as sharp as broken glasses, can cut the fault of the one who broke it.
That is why she protects it, in order not to hurt anyone who'll touch it.
Maybe not all, but some of us are afraid to give our sincerity, our heart and our whole being to someone. Because we have that mindset that people will leave, will hurt you and take that part of you as they break it.