If you're looking for manga similar to Mukuchi na Koushaku Reijou to Reitetsu na Koutei: Zensei Hirotta Kodomo ga Koutei ni Natte Imashita, you might like these titles.
Liddy, who was Japanese in her previous life, is now the daughter of a duke and engaged to marry the gorgeous Crown Prince Friedrich—despite her complaints. But her plan to lose her virginity to a stranger and break her own engagement backfired when she accidentally slept with the prince himself! These hot-and-cold lovers are still bound together, in the streets and in the sheets.
Leticia, a daughter of a duke, has her reasons for trying to get her engagement to a prince ended. She successfully achieves her goal, and the prince declares their engagement over. She believes all is good, until one day, the memories of her past life as a nurse suddenly come back! Because in her past life she had such a grueling job, in her new life, she wants to take it easy enjoying her favorite alcoholic beverages. She starts living in the countryside, hoping for an easy life, but she gets mixed up in one problem after another. A fantasy about a young lady who just wants a simple life, but is forced to run around trying to get the laid-back life she dreams about!
In her past life, Countess Sheila was Alexia, a queen who lost her life 100 years ago. Now, Sheila has worked her way up to the inner palace while hiding the fact that she is the reincarnation of the queen. But wait, why does King Felix looks just like Claus, a squire and her boyfriend in her past life?! The two of them reveal who they really are, and understand how each other feels... Well, that's what she thought would happen, but when he says "I can protect you as much as possible in this world," is he looking at Sheila, or he is he talking about Alexia? In their past life, the two were bound together by their promise that, "I'll always be by your side." But now they're beginning to grow apart...?!
Louise, a noble lady who loves reading and researching magic tools, leads a double life pretending to be her twin sister. Suddenly one day, her fiance breaks off their engagement and chooses to be with her sister instead. All seems lost to her when she also has to give up her dream of becoming a magic tool researcher, but a reunion with her first love, the first prince Lucius, saves her from her misery. As they spend time together reading books in the hidden archives and looking around at different magic tool shops, Louise slowly regains her confidence. On top of that, her heart flutters every time unconsciously sweet words leave the prince's mouth. The mood is perfect and it seems like it's seconds before they can finally be together, but the past she wants to keep hidden gets in the way. "How...do you feel about me?" He asks, but...I can't do it. I can't tell him. Meanwhile, her potential as a researcher begins to blossom and leads to... A true love fantasy full of misunderstandings between a magic tool-obsessed noble lady and a stoic older prince awaits!
A scandalous romance in another world! The noblewoman Lidiana, daughter of a duke, is actually the reincarnation of a modern Japanese woman who was tossed into this fantasy world. Although she’s engaged to the handsome crown prince, the last thing she wants is to marry into a polygamous royal family. Knowing that only a virgin can marry the prince, she devises a plan to lose her virginity to a mysterious playboy at a masquerade ball. Lidiana lands her masked Lothario, shares an explosive night with him, and goes to confess to the prince so she’ll be set free. The only problem is…the prince himself isthe masked man, and now he wants her more than ever
Renellette is the beautiful daughter of a Count, with a position, an education, and enough property befitting her status, yet somehow she can't get married. One day, while searching for a marriage partner, she meets a man who rekindles memories of her past lives, a stalker who interferes with her marriage every time Renellete reincarnates! She struggles to shake off the obstacles between her and a happy marriage in this life, but his shadow is always flickering behind her...
Aria, a young lady of an unremarkable noble house, was a high school student in her previous life. She was roped into attending a marriage interview with Prince Eugene, who's rumored to be an oddball, and it’s during this meeting that he suddenly makes a ridiculous claim — that he was Oda Nobunaga in his past life!! Well, that explains why the Prince still has yet to find a partner. However, Aria calmly accepts Eugene’s tall tale, which inevitably piques his curiosity… That won’t do! What if he finds out that I, too, have memories from my past life?! Thus begins Aria’s days of being aggressively courted by the world’s most powerful prince who’s capable of unifying entire nations!
Azalea, a duke’s daughter, was once known as the “Wicked Woman Who Ruined the Country” in her previous life and was executed on those false charges. All she wanted in her second life was to live peacefully without being involved in politics or power struggles… but for some reason, she was chosen to be Crown Prince Lotus’ fiancée. Lotus is a problem child that even his parents, the king and queen themselves, have no idea how to handle. Even though Azalea is being thrown into chaos by the eccentric actions of this extreme genius, gradually, she finds that she can’t leave the boy alone…
Qatora was once a valiant knight of the Razanate Empire who gave her life to protect a young imperial noble. The tragedy cast her into the primordial Light of Origin, which not only revealed to her a dangerous secret... but also reincarnated her! She now lives as Lyse Winslette, the humble daughter of a poor baron in a neighboring country, who is doing everything in her power to keep her distance from the empire because of the forbidden knowledge she possesses. Lyse thus works her days away at the royal palace of Olwen as a lady-in-waiting. And she’s rightfully mortified when she’s chosen to attend the visiting Razanate emperor. Little does she know that she’s about to learn another state secret that’s going to land her... an engagement to an imperial knight?! She’ll have to use all her skills—from this life and her last—to get out of this mess. Yet what is this strange feeling when she touches her fiancé’s hand? Just who is Sidis, and what secrets is HE keeping?
Countess Ashley lived her life as a black rabbit in the Demon Kingdom, but died at the hands of a brave hero. Now she’s reborn in the Tolpha kingdom, which is governed by his descendants. Suddenly, the king's brother, royal prince Clyde, becomes her fiancé. It's impossible, he's her enemy?! But Clyde is happy to embrace Ashley. "Give me a hug?" "I can't!" When she sees his face her heart skips a beat... Is it terror? Or is it love?