If someone were to receive a tremendous inheritance from someone they knew a long time ago, or barely knew at all, how would they be contacted? How would it be known not to be a hoax?

I assume most people know those whom they would receive an inheritance from fairly well, or know they were receiving one.

But what if it were a very distant relative, a childhood friend one hadn’t heard from in many years or decades. or someone met only once, but meant enough that the person left them an inheritance of tens of millions of dollars or more—maybe because of something they talked about, or for no reason at all?

Granted, this is extremely unlikely—all the more why it would be assumed to be a hoax or ignored.

But its kind of a ‘romantic’ idea—the sort of thing people hope for but don’t expect—the idea of implausible movies and novels

So, how would it happen if it DID happen? How would such a designated recipient be credibly notified? How would they know it was real, enough to follow through?