To see a blade in your dream suggests that you are making some difficult and important decisions. You need to be able to make clear distinctions between your choices. It also indicates that you are walking on a thin line and need to balance aspects of your life carefully.
To dream that a blade is broken in half indicates some ambivalence, confusion or ambiguity with some decision that you are trying to make. Up to now, your actions have been counterproductive. Alternatively, the dream means that anger is not the answer to solving your problems.