Regarding this, when you have your heart set on something?
have (got) your heart set on something. to want something very much, so that you would be very disappointed if you do not get it: She's got her heart set on ballet lessons.
One may also ask, where does your heart set? The human heart, which is normally about the size of your fist, is located behind and to the left of your breastbone, also called the sternum.
Consequently, what does it mean to set your mind on something?
phrase. If you set your mind on something or have your mind set on it, you are determined to do it or obtain it. When my wife sets her mind on something, she invariably finds a way to achieve it.
What does off by heart mean?
phrase. if you know something by heart, you can remember all the words in it without any help. We learned long passages of poetry off by heart.