* The document purports to be a genuine will, but its authenticity is questionable. (Meaning: The document claims to be a real will, but it might be fake.)
* The article purports to offer unbiased information, but it clearly favors one side of the argument. (Meaning: The article claims to be fair, but it actually leans towards a particular viewpoint.)
* He purports to be a skilled negotiator, but his track record suggests otherwise. (Meaning: He claims to be good at negotiating, but his past performance doesn't support that claim.)
* The rumors purport that the company is about to be acquired, but no official announcement has been made. (Meaning: The rumors claim that the company is being bought, but there is no official confirmation.)
Let me know if you'd like more examples or have any other questions!