Internalization is the noun: the process, or the result, of taking a belief, a rule, a feeling, or a way of behaving and making it part of who you are — so you follow it from inside, not only because a teacher is watching. In school talk, a child who has done this with kindness does not need a sticker every time. Though actually, the word lives mostly in classrooms, therapy, and academic writing; friends almost never say it over lunch. British spelling often uses internalisation with an s.