Have you not watched the anime?? I really recommend it. I've only watched the anime and not read this but its following the novel so it's more complete. Let me spoil you then
The reason she got adopted was because at the end of part 2, the High priest (fatty) conspires with some noble Viscount from a different domain to trick Myne into signing a slavery contract with him. They use a baby (who also has devouring staying in the orphanage) to blackmail her. Before this there had been multiple attempts to kidnap her, which leads to her using the pendant Sylvester gave her to receive his protection. This pendant he gave her actually contained a contract that allowed him to directly adopt Myne. Since Myne puts her blood seal on it, she immediately becomes his ward. When the High priest after defeating her guards and father (there's a fight scene here) almost puts her blood on the slave contract, the head priest (Ferdinand) shows up and stops the high priest. But the fatty insists that since she's hurt a noble she and her family should be put to death. Myne takes the pendant out and curses at Sylvester for deceiving her but Ferdinand notices it and realises what that pendant was for. He asks Myne if she would be okay with Sylvester adopting her instead of Karstead (as originally planned) in order to protect her family and she agrees. Then Sylvester shows up claiming how Myne has not committed any crime as she's his ward and therefore now a noble herself. Sylvester (is the Lord of the Domain) arrests the Viscount and the high priest (fatty, who is also Sylvester's maternal uncle btw) is executed. Therefore Myne has no choice but to change her name and leave her family forever, she does secretly meet with Lutz & Benno (as she's still the owner of Myne's studio and doing business with them) but she's not allowed to meet her family in a way that would reveal her true identity. It's declared to everyone around them that she's dead. So even if they ever come across her they must treat her like a noble not their family (Sylvester makes them all sign a magic pledge of sorts). She then leaves for the noble parts of the domain and that's where part 3 starts.
If you have any questions feel free to ask, I'll do my best to answer them. But please know my knowledge is limited to the anime.
I just checked Part 2 and it's pretty much complete. I'm not sure which chapter you got off from, but if you read it all it will answer your question. If not then hopefully my previous reply would help. I'm mostly following the anime so I won't be able to answer any finer details, maybe some novel reader could help you understand better. I hope my reply atleast helped you a littleヾ(❀╹◡╹)ノ~
More reason why I wouldn't want to proceed. I read this manga because I was addicted to Family-Oriented mangas these days. I love their family dynamics even when they were so poor. But learning that she had to leave her family because of such event, kinda heartbreaking for me.
Thankyou sooo much for the effort of explaining it to me.
Well, I really felt betrayed, kinda emotional HHAHAHAH
Like if she was me, and I had no choice but to leave my family and be adopted by someone else when I could become rich with my family without someone else's name... I'd rather dieeeee
But given that she's not the real daughter because she came from another world... that is probably why she has less attachment to them.
Thanks for the long long explanation, there, I wouldn't need to go through the whole manga just to cryyyy in the end

I was so invested with her moments with her family, then jumped here and found out she got adopted and has a different name now. I dunno what happened and how it happened, so I can't continue reading it huhu
I feel like I was betrayed. Broken, that is. I wanna cry. Can someone spoil me? Why was she adopted thouuugh!?