It is a kind of love to the little one. As a term, "cherub" is used to describe a character "like a cherub". According to the specific characteristics of the characters, this figurative usage has multiple meanings.
One can be used to refer to the figure's appearance and image is lovely; the other can be used to refer to the character's character, which is kind and pure, warm and popular. You may promise a desire, your desire will realize, the cherub forever will also look after you.