The Talmud interprets Esther’s statement to Mordekhai, “and if I perish, I perish” (Est. 4:16), as follows:
“As I am lost to my father’s house, so will I be lost to you” (Megilla 15a).
But Rabbi Tzadok HaKohen of Lublin offers another interpretation:
“As I am lost in my worldly existence, so will I lose the next world” (Likkutei Amarim 16).
Until now Esther had associated with Ahashverosh under compulsion, but now she must continue their relationship of her own volition.
To do such a thing, Esther must go beyond her ordinary limits.
Until this stage, Esther had preserved her innocence, for her entire relationship with Ahashverosh had been under duress.
The moment it ceases to be under duress, she forfeits her moral and spiritual high ground.
Though all she does is for God’s sake, she nevertheless seemingly loses her portion in the World to Come.
–Rabbi Adin Steinsaltz
From Talks on the Parasha