How do I bound the movement of a sprite within a shape?

How do I lock the position of a sprite so that it cannot move outside the white box shown above?

How do I lock the position of a sprite so that it cannot move outside the white box shown above?

The heart inside the box?

You could use 4 Sprites, one for each side or you could use a tilemap.

Couldn't you just clamp it since it's a rectangle?

clamp(x, lower, upper)

Return lower if x is less than lower, upper if x is greater than upper, else return x.