I’m trying to remember the name of a Japanese fantasy romance manga.
The female lead is a neglected noble girl who is constantly compared to her beautiful sister. Her family plans to marry her off think, so before running away she decides to spend one night with a handsome stranger.
The guy turns out to be the male lead/hero (I think he had red hair on the cover but i can be wrong), and he has a personal rule that with the first woman he sleeps with becomes his wife.
There’s also a priestess/saint character who was isekai’d from Japan. At first she seems suspicious or antagonistic, but later it’s revealed she’s actually a good person. She’s also very flirtatious/open about sex.
It’s a black-and-white Japanese manga (not a manhwa/webtoon), and I think the title was very very long.
Does anyone know this manga?
Since i dont think i will ever get my "curently reading list" back i ask you guys if you can help me, im searching for a Isekai/reborn MANGA;
Unfortunately, I don't remember much about it, but I do know that FL and the Saintess were both reincarnated/isekaid from Japan into this game/book. FL's family (stepmother, father, and stepsister) treat her terribly, so she plans to leave at some point (I don't remember if it happened or not), but FL sleeps with ML, and ML, the Hero/knight, was like i marry the person i slept with; ultimately, he falls in love with her.
Also another one similar to that, fls family loves her little sister more, fl is a saintess and her little sister wants to be one too as she doesnt get powers she tries black magic as she "falls" in love with the villain.

does someone know how to post a new manga or new chapters here?
New chapter: open the story page where you want to add a new chapter and you can see this
https://www.mangago.me/home/photo/56814861/
New manga
https://www.mangago.me/home/photo/30121046/
for new manga, use the second method
Thank youuuu