Albert Barnes Commentary Esther 7:4

"for we are sold, I and my people, to be destroyed, to be slain, and to perish. But if we had been sold for bondmen and bondwomen, I had held my peace, although the adversary could not have compensated for the king`s damage." — Esther 7:4 (ASV)

The king now learned, perhaps for the first time, that his favorite was a Jewess.

Although the enemy ... – that is, "although the enemy (Haman) would not (even in that case) compensate (by his payment to the treasury) for the king’s loss of so many subjects."