Next to the culture icon next to your character portrait, it should be right next to your character portrait, represented by the candle. To do this, you can visit the faith page in the lower left part of your user interface. You must first learn more about the principles and doctrines of your faith. It is a useful tool for expanding your empire and promoting your character's faith to others.
Yet, if you improve your relationships enough, this is sometimes overlooked. It can be a vicious cycle when trying to engage other leaders politically.
There is a good chance that a good majority of the characters of the Catholic religion do not like your character more because they regard those of this religion negatively. For example, suppose your character is from Ásatrú. It determines how many other rules and characters in the game see you. It is a measure of your character's devotion to their faith. Piety is one of the four main forms of currency in Crusader Kings 3.
