Nidome no Hatsukoi ga Kojireta Majo wa, Tokimeku to Houden shimasu

Diana, a baroness, has become a recluse in a country villa after being traumatized by the words of her first love, Julius. She spends her days making magical tools, which is her forte, and becomes a craftsman who is even called the "Witch of Römer". One day, Diana goes to an evening party in the royal capital, where she has a chance encounter with Julius. While she tries to forget her faint feelings for him, her brother, who is too much of a sissy, develops a "ring to repel men" that repels the insects that come close to Diana, and it discharges into Julius...?