Here are some examples of how to use "gullible" in a sentence:
* "The scammer preyed on gullible people who were eager to make a quick profit."
* "He was so gullible that he believed the salesperson's outrageous claims about the miracle cure."
* "Don't be so gullible! You can't believe everything you read online."
Let me know if you'd like to see more examples or have any other questions!