It's just a matter of success and failure; once it fails, you won't finance again. But if the person is winning, that would help you earn consistent profit, provided he sticks with the same setup.
That's how a gambler should think. It shouldn't complicate things. We're all in this to expect two possible outcomes: either we lose or we win. Similarly, when trusting a person, it's akin to a gamble with agreed-upon terms. If they succeed, we win; if they fail, we lose. It's that simple, right?