Jason_17_

It happened all of a sudden, and she didn't expect them to bring a mirror search artifact. Before that artifact, regardless of what she said, it wouldn't work, and she couldn't manipulate the artifact as easily as Ji Bozai without exposing herself, and I think she took a back seat because that was the best option there.

She lies because she has lived her whole life lying to everyone about her identity; it's not that easy to just reveal her identity, and there is no guarantee what would happen if her identity were revealed. She wants to at least cure herself and gain the power back to protect herself before telling the truth. She trusts him, but she doesn't know if he will give her the golden millet if he knows about her condition. She couldn't gamble with her life, so she chose the safest option she could think of.

For the past seven years everyone has seen Mingxian as a man. so Ji Bozai might be thinking that she must be related to Mingxian and not a man turning into a woman.

I think she's already started to develop feelings for him. Before episode 10, she normally tried to avoid kissing or crossing boundaries, but she didn't seem to be thinking about them as much now. Whether or not she fell for Ji Bozai, even her spiritual beast hesitated about answering to her master.