* Simple: The constant stream of bad news led to a growing disillusionment with the political system.
* With a Cause: Her volunteer work at the animal shelter left her disillusioned with the way society treated animals.
* With a Person: The news of his betrayal caused a deep disillusionment that shattered their friendship.
* With a System: After years of working in the corporate world, she felt a sense of disillusionment with the cutthroat nature of the industry.
* With a Dream: The harsh reality of her situation quickly dispelled her romantic illusions and left her feeling disillusioned.
You can also use "disillusioned" as an adjective:
* Example: He was a disillusioned ex-soldier, cynical about the promises of peace.