A person (usually The Hero) has his entire motivation built around protecting a girl. Most of the time, it's his Love Interest, but it could also be his little sister, or his daughter. (Female cases do occur as well, but they've usually got a subtly different tone to them, and don't really fall under this trope - with the exception of lesbian-love-interest situations, where one of the girls basically play the 'male' half of it.) In Anime, the sentence "Zettai Ni Mamoru!" is likely to get used - if not spoken aloud, then thought. Examples of Declaration of Protection include: