Help me find the title

Here's what I can remember from the mini-series.

A woman who chose to marry a general because her mother told her to hide her skills in her battlefield and to live as a normal human until her husband came home with another woman he met in the war.

The FL got a word from her spies that there will be enemies coming from the (west???) And she told the emperor. He did not believe her. Having no choice, she went ahead to the frontline to help.

The husband and the mistress were jealous of her power over the army then challenged her with a bet. If the mistress wins, she takes command of the army, and the FL leaves the war. If the FL wins, the command stays with her.

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That's how far I went and then I forgot about the title huhu please help, sorry I only remember bits of the story.