The Matchmaking of Marielle Clarac(2019)

Marielle Clarac no Kyuuai

Book 6 of the Marielle Clarac series.

Newlywed Marielle is settling into life as a married woman. Now that she’s moved in with Simeon, the gorgeous military officer who happens to be her ideal man in every way, she wants to spend every moment she can with him. However, it’s not long before their lives take another turn as Prince Severin’s troubled love life comes to the fore. Will Marielle’s friend Julianne return Severin’s affections, and will the royal family accept her? To help out, Marielle is brought to the palace under the guise of being a personal attendant to the queen. As a romance author, amour is Marielle’s specialty, so she’ll do what she can to bring the crown prince and the lowly baron’s daughter together. Her task is tricky enough—but then an assassination plot throws everything into chaos! The sixth volume in the adventures of the now happily married fangirl who obsesses over her husband and everyone around him!

(Source: J-Novel Club)