[mass noun]disappointment resulting from the discovery that something is not as good as one believed it to be 幻灭,失望
verb
[with obj.]cause (someone) to realize that a belief they hold is false 使信念破灭 if they think we have a magic formula to solve the problem, don't disillusion them. 如果他们认为我们有可以解决问题的神奇方案,别使他们失望。