Japanese phrase
ちゃんと返します。 cha n to kae shi ma su
Meaning
I'll make sure to return it.
When to use it
Promises to return something as agreed. It sounds responsible and reassuring when speaking about a borrowed item.
Example dialogue
その本、借りてもいい？ so no hon ka ri te mo i i
Can I borrow that book?
いいよ。明日までにちゃんと返します。 i i yo asu ma de ni cha n to kae shi ma su
Sure. I'll make sure to return it by tomorrow.