If you describe someone as gullible, you mean they are easily tricked because they are too trusting.
例句
What point is there in admitting that the stories fed to the gullible public were false?...承认向轻信媒体的公众提供了不实报道有何意义呢?I'm so gullible I would have believed him.我很容易上当,可能会相信他的话。
英英词典释义
Noun
1. tendency to believe too readily and therefore to be easily deceived