If you're looking for manga similar to I Got Pregnant With His Majesty's Child: A Biography of Queen Berta (Light Novel), you might like these titles.
The youngest princess of the country of Stellaus, Marietta, was betrothed in a political marriage to the General of the great militant country, Oltaire. General Belvant was often said to be strong, a fierce and terrifying god of a warrior. On the other hand, Marietta was a delicate flower of a princess. Everyone felt pity for poor Marietta’s situation, however, the truth was that Marietta found the General very dreamy… The story of a 30-year old General with a scary face (who was actually quite nice), and the tiny and adorable 18-year old Princess in their times of conflict and of lovey-doveyness.
Duchess Leticia Dorman has been betrothed to Crown Prince Clarke since age seven. She was once a rambunctious and free-spirited child, but the strict education she’s receiving to make her a fit future princess has really put a cramp in her lifestyle. Her only hope is that the prince might someday take an interest in someone else—so when Clarke shows up to a royal ball with an unknown woman at his side, Lettie is overcome with delight, presuming her dream has come true and her engagement has been broken off! She wastes no time retreating to an easygoing countryside life, but her newfound peace is cut short when the prince shows up and claims she’s still his fiancée! Clarke is determined to win Lettie over and marry her, while Lettie is determined to resist his charms and escape! Who will emerge victorious in this heart-pounding battle of wills?
Agnès is engaged to the crown prince, but much to her dismay, he declares that their engagement is off. Since the prince will not return her love, Agnès decides that she must do what is necessary to protect her family and herself. She commits an unfathomable act, but surprisingly, the prince becomes fixated on her! Will this couple get another chance at love? Or will their stubbornness get in the way?
16 year-old Princess Rosemary is furious with her older brother Prince Mash. Without her consent, he has promised her hand in marriage to Prince Lionel of Yurinera. Although the two kingdoms are neighboring countries, they are worlds apart. Arudera is a small, poor country filled with an abundance of greenery and untouched nature, while Yurinera is a very large and wealthy nation. Princess Rosemary decides to disguise herself and journey to Yurinera to sabotage the marriage proposal and sneak a peek of her husband to be. But when she arrives she discovers Prince Lionel to be completely different from the cruel and cold-hearted person he is rumored to be. Despite her original plan, she finds herself falling in love with him!
Abandoned as an infant in spite of her royal blood, young princess Elsa has lived the life of a beggar. Now bitter, foul-mouthed and vengeful, she feels no gratitude when the seers who abandoned her in the name of prophecy retrieve her to use as a royal pawn by marrying her off to the cursed Prince Claudius of the neighboring kingdom Red Ark. Elsa loudly curses them and swears to ruin their plans for the marriage being forced on her, so the seers decide to keep the princess's foul mouth from ruining their scheme- by stealing her ability to speak!
The small country of Adarshan recently conquered a territory of the Castoria Empire. To create an alliance between the two countries and secure new border alignments, the victorious Adarshan general, Alexid Deke Adars (the king's younger stepbrother), was forced into a political marriage with Castoria's sixth imperial princess Justinia. But she's only 10 years old!