Many people get confused when speaking of the Sacred Heart of Christ and the Immaculate Heart of Our Lady. They're unable to remember how to recognize which is which, as well. The picture above shows first the Sacred Heart of Jesus. Next comes the Immaculate Heart of Our Lady. You'll notice that Christ's Sacred Heart is encircled with thorns and topped with a Cross while Our Lady's Heart is surrounded by roses and, as it's often depicted, pierced with a sword (sometimes it's shown as pierced by three or seven swords).
The third heart above is the heart of St. Joseph, too often forgotten. But he shouldn't be. Fathers are so important, and now more than ever, we need to embrace St. Joseph as a patron, asking him to help fathers and the cause of fatherhood. You can recognize St. Joseph's heart by the lilies surounding it.
All three hearts are topped by flames symbolizing divine love.
Note that when Jesus, Mary, and Joseph are referred to, they're almost always mentioned or depicted in that order.