At many companies, the hiring manager has the recruiter make the offer. This is another mistake. The hiring manager should personally make the offer and sell him/her on the role and company. You may have chosen the candidate, but that doesn’t mean the candidate has chosen you. You must assume that good employees are being actively pursued by other companies, including their current employer. There is always the risk that you could lose the candidate. Nothing is certain until the day they report to the office.