Fpr your question yes it's heavily implied that Amo was sold to that old man as a "wife", it implicitly implied he was consistently sexually assaulting her and maybe even rape. keep in mind she's was sold about 5 or 6 years old and when she made an appearance she was about 14 yo so that sa probably have been going for a long time. Also it's clear that he was manipulating her into thinking that was love and when she mentioned her heart war racing (probably of fear bc of getting sa) he told that was love which she only knew it was wrong when she met the "angel" and for the first time her heart raced in admiration and love and from that moment knew that that old man was not her true love and she accidentally killed him to protect what was precious to her.
TL;DR yes it was heavily implied she was sold and sa and groomed as a child.
Honestly I’m a little dense..but did the author literally imply that Amo was sold off/kinda trafficked, SA’d AND groomed till the unknown “angel” came changed her perspective leaving her alone till the cleaners came?? Like yo..I started reading this because I was too impatient to wait for the new episodes in the anime and it was literally the best idea I’ve ever had. My limit for any Manhwas and manga are about 60-70 chapters before I get bored, but this is literally so interesting I binged this and finished in about 2 days. I HIGHLY recommend for anyone who started the anime like I did and came to read it for more. (๑•ㅂ•)و✧ლ(´ڡ`ლ)