"打破人的幻想" can be translated into English as "shatter someone's illusions" or "dispel someone's fantasies".
"Shatter someone's illusions" implies a forceful or sudden destruction of unrealistic beliefs or expectations.
"Dispel someone's fantasies" suggests a more gradual or intentional process of clearing away false or unrealistic ideas.
Both expressions are commonly used depending on the context and tone you wish to convey.