I have my heart set on this car,I am willing to borrow money to buy it.

我决心要买这辆车，我愿意借钱来买。

have one's heart set on... 表示一心一意要去做某事或得到某东西。

I have my heart set on studying abroad.

我一心一意要到国外读书。

What do you have your heart set on?

有什么事你们是一心一意想去做的，或有什么东西你们是决心要拥有的。