It's hard to understand someone fully, even when you've known them for years. People evolve, change, and adapt. Therefore, it is not surprising to learn that during the hiring and selection process, it is nearly impossible to predict how someone will perform, let alone if they're the right person for the role.
Although there are many tools to help organizations learn about a person: resumes, learned skills and experience, education, training, structured job interviews, and background checks, none of these can help predict an individual's future performance. The usual methods tell us about their past and present, but you need to select for the future.