31-banme no Ohi-sama

A young woman from a rural area, born to a noble known for cultivating medicinal herbs, is selected as a potential consort for the king. She is designated as the "31st" candidate, meaning the king will only visit her on the 31st of each month, a date that occurs infrequently. Given a residence with a lush garden, she uses it to grow vegetables and herbs. Her kindness and strength draw attention, and several knights become interested in her. Eventually, the king also takes notice.