Why does it sound believable?
Fake news makes clever use of the human characteristic of prefering to believe information that confirms our own opinion. This means that if you are confronted with a post that fits right up your proverbial alley, you are more inclined to believe it. This is called 'confirmation bias'. As a result you can quickly end up in a so-called 'filter bubble'.
In this section you can read more about confirmation bias and filter bubbles. You will read how this affects your assessment of information and the information you are offered.