What bra to use for a deep V-neck?

If you're wearing a shirt or dress with a deep V-neck neckline, the best bra to wear is a deep plunge bra. 

These bras typically feature a V or U wire at the front center gore, which allows the center of the bra to dip below the bra line. If you're looking to enhance your cleavage, look for a deep plunge bra that has padding that pushes breasts towards the center.