disillusion about(或at,with)

• 对(某人或某事)不再抱幻想，对(某人或某事)感到失望：

  Parents are disillusioned at the son's behaviour.

  父母对儿子的所作所为感到很失望。

  They have become disillusioned with the president.

  他们已对总统感到失望了。