alt Hacker NewsWhat? Hiring is a contract between employer (company entity) and employee. No individual "you" can hire anybody except through the company's official process. If HR says "no we won't extend an offer," a lowly HM extending an offer would be clear-cut fraud.
Managers usually have the authority to bind the company to an employment contract. Even if they don't, the rule of "apparent authority" often means the employee can still sue.
In the USA this is mostly theoretical since HR could immediately fire the employee due to at-will employment.
But in Canada, it's a much bigger issue due to labour protections.
e.g. Many managers at American multinationals gave assurances over email to employees about work-from-home arrangements. Then the company does a huge RTO push.
When the employee refuses, HR discovers they can't fire the employee without a hefty buyout.
Best not to give assurances if you're managing a multinational team.