Sounds like awful monetization. Dating site issue is right. Your best candidates (so ideally, all the ones you vet) won't be long term subscribers. And sadly, there's way too many grifts in the job system where a candidate paying is a red flag. You'd need to offer the candidates something of value to justify that. Not just "a promise of no ghost jobs").
Is there an issue with the usual recruiter pipeline where you can charge the company some percent of the hire once they get hired? Candidates get hired, company pays a little extra on a successful hire, and your profit incentives come from quality to offer for the companies (hopefully).
The main issue is that it assumes that companies genuinely care about an efficient hiring pipeline. And I've been very cynical in recent times...