Kusushi no Majo desu ga, Naze ka Fukugyou de Rikon Daikou shiteimasu

Carla is a down-on-her-luck witch whose skills aren't up to snuff when it comes to both magic and her work. Although her main business is running an apothecary that's been in decline ever since her master passed away, she also runs a divorce agency on the side (even though all of her clients seem to reconcile, for some reason). One day, Carla receives a request she can't refuse. The queen herself sends Thane, a knight who makes no effort to hide his distaste for witches, to pass along her message. Carla isn't a fan of knights herself, leading the pair to fight like cats and dogs...but maybe first impressions aren't everything!

(Source: J-Novel Club)