Easiest way to make sense

How about you sell this to someone else and then come to me with their feedback, that way I'll feel a lot better (In other words, affiliate marketing). You need to make one good sale to brag about it to the next potential customer. Similarly, when talking or writing about something, if you can give a good reference, then there is nothing like it. People believe you if you back your idea with a reference.

It's a fact if you believe in it.

Google uses this concept to rank pages online i.e. if other websites talk about your website/web page, you are deemed to be a good source. People might talk crap about you, but still, people take an effort to praise/curse you. If other sites refer you, then you are relevant.

The easiest way to make sense - get a reference or a recommendation.