જેના જેવા ઢંગ તેના તેવા રંગ; ચંદને ઘાઈ માછલી, પણ છૂટી નહીં ગંધ.

jēnā jēvā ḍhaṁga tēnā tēvā raṁga; caṁdanē ghāī māchalī, paṇa chūṭī nahīṁ gaṁdha.

Literally: As one's manners are, so are one's colors; the fish was washed in sandalwood, but the smell did not leave.
What it means: One's true nature and inherent flaws cannot be washed away or hidden by superficial improvements.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) · 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.