The toughest thing about a broken engagement is to rebuild the faith and capability about building another future.
You were engaged. You were tied to somebody. You were obligated to have a lot of dreams and plans about the future of you and him.
Suddenly the entire castle cracked down and you are standing there barely without a shelter.
You have to stand tall and look up and manage a future for yourself. This can be every exhaustive. And sometimes you will blame yourself for not being good enough by the time you were with him.
Love is always about the future. If it is broken, your future is broken.
The hardest part to get rid of a broken engagement is to be confident about your being and to be capable to have another "future".