They did not live in the same house, she was put in the detached building. Which in the case of a great noble's estate could be a couple minutes or so of walking distance.@Dali_Felizardo: i still don't understand, they lived in the same house, and the youngest child distanced herself from the others, then attempted suicide not only once, yet they all just ignored it. The gramps, who has been the head of the family, didn't spare a moment to investigate why his granddaughter wanted to die, only assumed that it was her own stuff. While it was true that the original Senianna had bad reputation, wasn't it the adults' responsibilities to fix anything wrong with the kids in the household? The negligence was strong in this series.
Even if she lives in a detached building, it would be still the same estate, which mean the same house. That woman can tell lies but the old man still get responsibility for child neglecting. It happened in his house, he cannot say he didn't know anything about it.They did not live in the same house, she was put in the detached building. Which in the case of a great noble's estate could be a couple minutes or so of walking distance.
And the building was managed by the woman who could manipulate every information inside it.
Senianna was also "raised" (neglected and abused) for years by this lady, and most likely manipulated from a young age. It's possible that she's had that gloomy behaviour ever since she was young due to the abuse and it's pretty common for abused children in reality to not seek help.
So, in conclusion, either the suicide attempt was covered up or her abnormal bevahiour became so "normal" that they didn't even think twice when she did it. Many years of being like that makes people accustomed to it, especially since they don't know her much since she did not try to speak to them and she even only knows them through rumors too. She lived like she was a corpse in the eyes of the unenlightened.
She even had depression due to all of it, I doubt depression was studied in this fantasy world, even in ours it's only recently that it's been focused on. (Even then it's only a bit. Awareness helps 🙏.)