Seri Ibuki

Nao, a 23-year-old office worker, grew up as the one girl in a household where her three brothers and parents were all obsessed with muscles. Nao managed to find a job and leave her house of meatheads, but is forced to return home when her office is struck by layoffs. However, she gets pissed off and runs out when she discovers that her room has been invaded by her brothers. Her big brother, Subaru, runs into the park to get her, but their argument is broken up by 35-year-old associate university professor Asuka Himori. The two of them end up meeting again at a marriage mixer and they end up hitting it off. Tonight's their first night together... but when Nao sees Asuka's naked chest, she can't help but run away at the sight of his muscles...!! No one said that a serious professor would be that muscular!! And it's not just his body, but his personality, too!? Source: Renta!

When Ritsu's apartment was burned up in a fire, she was rescued by Sagimori, a professor at the university she used to attend. Ritsu, who had lost her parents and had nowhere else to go, was invited to stay the night thanks to Sagimori's good intentions. She was told to stay away from one room in particular, but then she accidentally peeked into Sagimori's unusual secret! Knowing that his fiancé ran away on their wedding day and was still missing, Ritsu had a misunderstanding...? He promised that he's not actually interested in real women, but he offered her a contract marriage!? (Source: AI Production, translated)

From Snuday Scans: “Now that you’ve become my wife, no matter where I kiss you, you can’t refuse.” Ea is the last Princess of the Kurvea kingdom. Because she was born with blood-colored hair on the night of a lunar eclipse, she was considered a child of the God of the Underworld and was abandoned as soon as she was born. Nineteen years later, while living in the forest together with her falcons, Ea is suddenly proposed to by a man named Ardol who says he’s conquered her country. Originally, he was just a knight, but he became the upstart “Tyrant King” after the entire royal family died. In order to become the rightful ruler, Ardol seeks out Ea, the last remaining member of the royal family. “I don’t think of you as a king that only knows how to kill. Even your magic was beautiful.” Although Ardol is said to be a ruthless and cold man, he can’t help but gradually be attracted to Ea, who’s completely different from how he imagined. This is a fantasy love story between two people who have never known love.

An office lady in her thirties who works in the secretarial department, Aina Tanaka, is engaged to a rich heir and was supposed to have a smooth sailing life. However her fiancé suddenly dumped her for a junior colleague. Trying to get over the breakup, she got drunk and collapsed on the street. Then she was saved by a young man... and they ended up spending the night together! She was worried about having committed a crime, but the young man, after having heard of her plight, said he's about to turn 19 and offered to marry her under an arranged contract. Aina wanted to let her ex-fiancé think that she'd moved on, so she agreed... But on their wedding night, it turned out that the young man was an inexperienced virgin...? (Source: Amucomi)