The neckline forms two curves that resemble the top of a heart and is called the sweetheart neckline. The round arches cover the breasts, with the V shape falls between them. This neckline creates an illusion of slimmer shoulders and enhances the bust in the right place. Even with many other necklines (square, straight, halter, etc.), the sweetheart neckline remains a popular choice.The semi-sweetheart neckline is very similar to the sweetheart neckline, but the V shape in the middle of the two curves is less prominent (almost not noticeable) than in the sweetheart neckline. The top part of the bust is softened with less round arches and gives off sweet vibes.