Further halve a half of the middle, as shown in the picture.
We draw a smooth line from a point which begins slightly higher than ¼ heights and to be on the middle of a rectangle, further connects to certain points which we put down earlier.
Draw the same line on the other hand. That was more exactly you can draw a line on the middle of heart and a ruler to measure distance from this middle to the line of heart and to postpone the same distance on the other hand. So to do several times falling down, and then to connect these points.
We erase all auxiliary lines and we paint over our heart in red color.