Sansa knows, standing on the steps of the Great Sept, staring into Joffrey's triumphant eyes, the blood her father soaking the stones and all the Lannisters' beautiful promises ringing in her ears, that Starks have always been the best liars.

Night gathers, and now my watch begins. It shall not end until my death. I shall take no husband and bear no children. I shall wear no gowns and no jewels. I shall live and die at my post. I am the sword in the darkness. I am the watcher on the walls. I am the shield that guards the realms of men. I pledge my life's blood to the Night's Watch, for this night and all the nights to come. -The Sisterhood of the Night's Watch

There must always be a Stark in Winterfell, or: Sansa goes home.