be (dead) set on (something)
To have a strong (and sometimes inflexible) desire for something. We were all dead set on traveling to Spain for the summer, until Lizzy broke her leg and we had to cancel it. I wanted to spend the money on a new car, but my husband was set on getting new furniture for the living room.
be (ˌdead) ˈset on something/on doing something
want to do or have something very much; be determined to do or have something: She’s dead set on leaving her job and emigrating to Canada.