ધણીને સુઝે ઢાંકણીમાં, પડોસીને અરીસામાં પણ ન સુઝે.

dhaṇīnē sujhē ḍhāṁkaṇīmāṁ, paḍōsīnē arīsāmāṁ paṇa na sujhē.

Literally: The master sees in a small lid, while the neighbor cannot see even in a mirror.
What it means: An expert or owner understands an issue with minimal information, whereas an outsider remains clueless despite clear evidence.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1921) · read from the scan by machine — the Gujarati itself is unchecked · English is machine-made and nobody has checked it yet

Heard it differently, or know we've got the sense wrong? Tell us — that is exactly the kind of correction this needs.