Infiltrate an enemy city and free the lord (Mount Blade 2: Bannerlord)

Hello, how to be? There is a lord in prison in the city, I want to save him and not capture the city. When I drive up to the city, climb out the menu: 1. Talk to anyone. 2. Change clothes and sneak into the city. 3 Besiege the city. ATTENTION ITSELF QUESTION: Why Infiltrate the city is 0%??? Can someone tell me how to increase the chances, or at least tell me what it curls from