To the point that she actually fought alongside He-Man in the final battle of the series against Skeletor and Crita.
(Shameless self-promotion/self-indulgence: I actually took her to the next step and had her replace NA He-Man as wielder of the Sword and the Power--in a radically different way--after the latter fell victim to pride and despair and became the villain 'Nemesis'. I never told their story after the War of Grayskull, but even after Nemesis was redeemed, Mara was going to be the Champion and wielder of the Sword of Hope--Adam was too damaged by what he'd done.)