set (one's) mind on (something)
To be resolutely or inflexibly determined to do or acquire something. When I was a little boy, I set my mind on becoming a fighter pilot. When Janie sets her mind on a new toy, she won't give us a moment's peace until we buy it for her.
set one's mind on someone or something
Fig. to be determined to get or have someone or something. I've set my mind on Dave. I have to have him on my team. Jamie set her mind on the red sports car.