ચોરની નજર ચાર, ધણીની નજર બે.

cōranī najara cāra, dhaṇīnī najara bē.

Literally: A thief has four eyes, while the owner has only two.
What it means: A wrongdoer is always far more vigilant, alert, and focused on finding an opportunity than the unsuspecting victim is on protecting themselves.

Also said as

ગુજરાતી કહેવતસંગ્રહ (Gujarati Kahevat Sangrah) (1923) 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.