⟩ Why should I hire you as Lead Generator?
This is what it really comes down to. They’re a salesperson. So have them sell you on why they should hire you. The best salespeople will be able to give you three or four concise, compelling, and powerful points as to why they’re best-suited for the job.
If you seem to have trouble hiring the right candidates, your issues may go beyond simple interviewing technique. Maybe you’re recruiting from the wrong pools of candidates. Maybe your job descriptions are poor.