Charles Ellicott Commentary Esther 2:10

"Esther had not made known her people nor her kindred; for Mordecai had charged her that she should not make it known." — Esther 2:10 (ASV)

Esther had not shewed ... — From the hope on Mordecai’s part that she might pass for a native Persian, and that her Jewish birth should be no hindrance to her advancement. The king does not learn his wife’s nation until some time afterwards (Esther 7:4).