How would I make this Frame only be visible inside of this ImageLabel?

I'm currently working on a health Gui, and I'm running into this very annoying issue.

First off, let me explain that the health Gui is a heart, and the heart is an ImageLabel. There is a frame that will move depending on your health, however, I want that frame to be invisible if it is outside of the heart.

I have used ClipsDescendants, however the problem with that is I cant resize the borders of the ImageLabel or the heart becomes too small, too big, too stretched, etc. I've tried using a seperate frame as the borders, instead of using the ImageLabel as the borders, however, I cant make it exactly inside of the heart.

Is there any way I can do this? An explanation would be nice.