I'd add the caution that you should have clear criteria for what represents success in the job, and the timeline. If the candidate doesn't meet those criteria

I'd add the caution that you should have clear criteria for what represents success in the job, and the timeline. If the candidate doesn't meet those criteria in that timeline, you both should agree that it isn't working. My previous job was running a small Sys Admin consulting company. We hired 4 people over the years who definitely fit into the "not proven" category, with very mixed results. Two really struggled: One of them was "ok" but needed a ton of management, the other never really got a basic level of proficiency despite spending most of a year "studying" and working at the elbow of various masters. One worked out really well and was a great worker. I feel like there was another one, but I can't dredge up the specifics. The proven people on the other hand were mostly rockstars. The one that wasn't was largely due to my mismanagement of them. So: Yes, absolutely hire the unproven. But have a plan.