Sometimes the evidence is difficult to summarize, it could be just some statistical evidence that your System 1 has generalized after seeing hundreds of examples, or some kind of “X strongly reminds me of Y” where of course there are both similarities and differences between X and Y and you don’t fully understand why the similarities feel crucial and the differences irrelevant but they definitely feel that way for some reason.
And if you know that you can’t the case legible, your options are limited to:
say it, without providing hard evidence
don’t say it, but keep thinking and acting on it
hide it even from yourself
and the options lower on the list seem worse than those above them.
Can you reduce the impact somehow? What is the part that sucks most: is it a personal confrontation you’d rather avoid, or knowing that you made the other person’s future more difficult financially? If the latter, I can imagine some preparation to reduce the impact, for example make a mandatory savings account for everyone where you will put 5% of their salary, and then give them all of it at the end—not sure whether something like this is legal, but approximately in that direction.