This is a perfectly lovely sweater, and a great contrast color for when I interpret.
With a little surprise in the back!
This is a “reverse applique” technique on this little heart. I pinned a square of pretty fabric to the inside of the sweater, making sure it was larger than the heart.
And yes, that’s permanent marker. No turning back now!
I sewed a straight stitch on the line, then carefully cut out the center of the heart. One more time around the shape with a zigzag stitch just to be sure it’s not going anywhere.