
What she felt for the Duke was gratitude for his respect for her and educating her. She respects him as a mentor and a dear friend. She is not a housekeeper, but a substitute until Jeremy is ready(mature enough or a knight) for the responsibilities that the title brings. The previous Duke needed an outsider (someone who doesn't know about the family, who has no factions and isn't involved in politics) to hold the fort until his heir was ready and prepared to step up. The reason Jeremy wasn't ready was because the previous Duke believed Jeremy was still childish and wasn't ready for responsibilities. For example, of Jeremy were to become the Duke and the incident with the sword with Nora had happened, then the Duchy might had fallen because Jeremy might have done this and that, the siblings would've been taught by the family and probably Jeremy might have died from either exhaustion or by the hand of his bride. After all, without a guardian Jeremy would've gotten one or all of the nobles who were close with the previous Duke would try to corrupt him and pressure him to marry their daughter. In short, people hungry for power would try to take hold of an unprepared childish Duke, who is entering puberty, by selecting a bride, stomping on the once great Duchy and endangering the family's honor and lives.
im kinda confused but did Shuli actaully love the previous duke? i know they had a contract as well but it seems like there was more maybe unrequited too