My suggestions:
1) don't rely just on an interview (they are notoriously poor predictors). Get them to do a bit of the job. Better still, get them to work in the Salon for a day - you'll know a lot more about them by the end of that. The fancy HR term for this is 'Assessment Centre', by the way
2) Make it clear that there is a probationary (trial) period of, say, one month. At the end of this you review whether you want the person to continue.
3) Keep an eye on your gut feelings during the process. On the one hand, they might be telling you something useful (our adaptive unconscious has been developed over 10,000+ years) but they can make mistakes (eg, you take a strong like or dislike to someone not realising it's simply because something about them reminds you of someone you liked/disliked in the past).