Is it a pup? Adult? What age?
Trained with what kind of livestock?
Are parents actual LGD's?
Depending on the answers your things to look for and ask will vary.
IOW- for example, I have several pups right now, they are 4 months old. They are full time with goats and kid goats, chickens, geese,turkeys. They are all trained to hotwire as well as field fencing. One is a watcher 2 are patrollers. Their temperaments are very different. 2 pups are dominant, one is not dominant but is not "passive" either, but is showing great promise as a guardian. Out of the two that are dominant one is a highly confident dominant with no issues whatsoever, laid back and easy going. One pup is dominant and very obstinate. She will remain here longer as she is much more difficult in correction. Her correction is all about the poultry.
Our new Anatolian male is very passive (we CHOSE him because ofthis) I have way too many dominants as guardians so I needed a passive male. Tiggs is as laid back as can be.... yet in his field when there is anything going on he is all over it. He is 5 months old and just recently alerted us to an issue- where we had 2 bucks hooked by a collar and were strangling. If the pup had not gone nuts we would have 2 dead goats.