From aeclectic tarot
The Fool, victorious over his enemies, is feeling arrogant, powerful, even vengeful. There is a hot passion in him that he can barely control. It is in this state that he comes across a maiden struggling with a lion. Running to help, he arrives in time to see her gently but firmly shut the lion's mouth! In fact, the beast, which seemed so wild and fierce a moment ago, is now completely at her command.
Amazed, the Fool asks her, "How did you do that?" One hand on the lion's mane, she answers, "Will power. Any beast, no matter how wild, will back down before a superior will." At that moment, the Maiden meets the Fool's eyes; though saintly and young, her look is knowing and filled with great power. "Likewise," she says to him, "there are many unworthy impulses inside us. It is not wrong to have them. But it is wrong to let them control us. We are human, not beast, and we can command such energy, use them for higher purposes." His rage quieted, the Fool nods, enlightened, and walks away knowing that it wasn't only the lion that was tamed this day by a Maiden's pure and innocent strength.
from tarot teachings
This is another Major Arcana card that doesn't beat around the bush - it's meaning is quite clear in both illustration and title. Looking at the card we see a great deal of strength - but what kind of strength? Is the young maiden exterting physical strength to subdue the lion? Her face looks serene, her posture is calm - she doesn't appear to be struggling.
Yes, the Tarot card meaning here is that of strength - but not purely physical. The young maiden in white (a symbol of purity) subdues the lion through a strength that is internal. Through compassion, love, patience, and cunning, she is able to calm the lion into retreating into a behavior that is more manageable.