"Regret? What do you know of regret?" Anakin argues, because all he can think of right now is regret. He regrets trusting the Chancellor, putting his and Obi-Wan's and Ahsoka's lives at risk for his false war. He regrets having even a small part in the thousands who'd died.

He regrets the lives his took with his own hand.

Anakin can feel Rey in the Force, her presence swelling to meet his own, no longer small and far away, but the knot in his chest is still there, the fire in his heart still burning.