it's a webtoon, a count daughter or something have one night stand to avoid being sold off to some old geezer, and she got pregnant, after a few years she is being sold off to a Duke, and the Duke turn out to be the father of her child.
http://www.mangago.me/read-manga/i_gave_birth_to_a_murderer_s_child/?IREO
Ah, thank you so much, I often forgot to put them in my reading list.
it's a webtoon, a count daughter or something have one night stand to avoid being sold off to some old geezer, and she got pregnant, after a few years she is being sold off to a Duke, and the Duke turn out to be the father of her child.