That man, has a face of Makoto but a hair of Nagisa... Also, Rin, you are a 20 year old wo...

Ok but listen not only was her emotional maturity hit since she was constantly abused and traumatized, but she was also treated as a kid for 7 years or so like to some extent it makes you become a little more immature

Emotional maturity differs from mental maturity and behavior, would she immediately forget her entire 20 or so years of existence over that 7 years where she should technically mentally mature, too?
Nah, author's style, alright! ┑(￣Д ￣)┍

And abuse teaches people, adults and children, to be cautious of others and to really be sensitive to dangerous situations. Though she has now lived many years in a happy healthy environment, a recovered victim would still have at least a heightened sensitivity to danger. So this means her instincts should have been telling her not to go near and trust her, which would already be an easy conclusions for nearly every healthy adult, but she ignored it in favor of trust and care. It's sweet that she decided to trust but also incredibly DUMB! Especially when a war in the demon realm is going on right outside and she's not been there very long. Yeah she decided to trust her maid over her personal guard.

Not only that but when she reincarnate, she remembers other past lives of misery that she had. So I don’t understand how she com be so dumb