hinamesh :

The phrase “I’ll protect you” in Japanese is often used in anime as a declaration devotion and commitment especially when said by a man to a woman and not a petition to be as her bodyguard (although that does come up now and again). It’s is often translated as just “I love you” in English. 

— TVTropes 

A phrase that usually be said when a person (usually The Hero) has her or his motivation built around protecting another person. Most of the time, it’s to his or her Love Interest. — TVTropes