All Targa needs to do is marry the First Minister. Mother has a well negotiated marriage ready to be signed, and it’s a very good contract.
Her other job will be killing whoever Mother orders, because Targa’s sword is The Wind Before the Storm, a blade even capable of killing the deathless saints. It is her arm that will give her Mother’s threats credibility.
In her former life, this task would have been easy, but Targa has reformed, choosing the path of the hero, so backing a bloody dictator is not compatible with her morals. Her two sworn and unbreakable duties lie in opposition, one to the gods and one to her mother.