No, I'm not thinking about feminine and masculine, nor about passive stereotypes and powerful stereotypes.
It's about attributes that are seen positively in both women and men.
A skinny, camp, gay man might not be described as masculine, because he doesn't tick the stereotypes of masculinity. But on the bitterly cold winter day when we stopped to help a cyclist who had been knocked down by a car, and my skinny, camp, gay friend covered the cyclist with his coat, and crouched in shirt sleeves next to him until the paramedics arrived, giving no indication that he was cold, not even a dramatic sigh of relief when he put his coat back on, he would certainly have been described as manly.
'Manly' implies a man behaving in a positive way, regardless of his appearance, mannerisms or sexuality.
'Womanly' is more complicated, because it encompasses both the positive behaviours and some feminine stereotypes that make others feel comfortable.
But manly applied to a woman implies unwomanly, and womanly applied to a man implies unmanly - yet both describe positive attributes.