From Longman Dictionary of Contemporary Englishset your heart on somethingset your heart on somethingto want something very much His father bought him the bike he had set his heart on. She had set her heart on becoming a hairdresser. → heart
Examples from the Corpus
set your heart on something• He's always set his heart on going to Simon's school.• He was not a man to give way easily and he had clearly set his heart on making her recognise her father.• By January 1768 they were back in Vienna, where Leopold had set his heart on securing an opera commission for Wolfgang.• So now, after all, there was something she had set her heart on.• I have held no office because Thou did not will it, and I never set my heart on office.• He's set his heart on a new bike for Christmas. 