If you find it please share
I don't remember if his twin sister was adopted by a rich family, but Lala did take his sister's place as a bride so that she could run away with her lover. The ML is from an influential and rich family.
https://www.mangago.zone/read-manga/lala_no_kekkon/
Omg I just realized I read it wrong. I thought you were looking for an mc who had a twin sister. I'm so sorry
Sure
It's okay hahahahah thank you <3
It was this one https://www.mangago.zone/read-manga/solar_eclipse/
I completely forgot about this one.
All I can remember is that the mc has a twin brother. His twin was adopted by a wealthy family but the mc was poor. His twin brother was supposed to marry someone but he took his place instead. The persons whose going to marry the mc was actually looking for him for a long time, he met the mc at an alley and they fought and I guess that person lose. I think he was a prince or a wealthy person. That's all I remember. Thank you for you're help (づ￣ ³￣)づ