ઠોઠ નિશાળીઆને વતરણાં.

ṭhōṭha niśāḷīānē vataraṇāṁ.

Literally: A dull schoolboy makes many excuses.
What it means: An incompetent person offers endless excuses rather than admitting lack of skill.
The English proverb Shah set beside it: He that knows least, commonly presumes most.

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.