* Simple: The movie really disappointed me. I had high hopes, but it was boring.
* With a noun: His performance was a disappointment to his fans.
* In a negative sentence: I tried my best, but I didn't want to disappoint my parents.
* With an infinitive: I hate to disappoint you, but I can't make it to the party.
* In a passive voice: She was disappointed by the lack of effort in his work.
Do you have a specific context in mind for how you want to use "disappoint"? I can help you write a sentence that fits your needs.