Depends on who "someone" is, what the "newspaper" is, and what was said with "said so".

In this case "someone" is a double Pulitzer Prize winner, and what was said was something of a nature that means the editor in any reputable newspaper will demand hard evidence, i.e. he will have the names of all the sources, and confirmed with at least some of them. If the story is a fraud (possible, look up Jayson Blair), the editor would have to be in on it, and it would be a larger scandal than the story itself, which really just confirms what everybody already suspected.

The story is as good as investigative journalism gets.

And yes, reputation matters a lot in journalism. Jayson Blair is a life coach today.