Wen Jiang's main purpose for returning home was to get some things and take a look at Nian Jian.
Nian Jian was indeed very honest. After being rescued by Wen Jiang, she had genuinely been investigating news about her mother. As someone unaware of the inside story, she had no way of knowing the truth about the System, nor did she understand why her mother had abandoned her years ago.
Even after learning Wen Jiang was from the nobility, Nian Jian didn't seek help. Being saved by Wen Jiang was already a stroke of incredible luck, and she couldn't bring herself to ask for more.
Besides, Wen Jiang didn't restrict her movements in any way, apart from not allowing her to leave the premises, and Nian Jian herself didn't dare to venture out.
