it is a little bit of trust and faith, sometimes.
i had an amazing experience with a guitar purchase on reverb, the guitar was mint and was packed incredibly well. my friend, bought a guitar on reverb and the guitar was as described, but the seller shipped the guitar in the original hard shell case, not in a shipping box. reverb has guides on how to ship a guitar, and even sells boxes, but obviously that seller didn’t know or care
there are both private sellers and companies online..let us know if we can help you on a specific guitar