What is the origin of the idiom "sweet nothings" and when to use it?

The phrase is thought to have originated in the 17th century; it can be better understood by breaking it down into its components. "Sweet" refers to something pleasant, endearing, or charming, often associated with feelings of affection or love. "Nothings" refers to words or phrases that may not hold significant meaning or substance. It is used to describe affectionate or loving words, phrases, or whispers exchanged between individuals in a romantic relationship. The term suggests that the content of these expressions may not have deep or meaningful substance but are still cherished and appreciated for the emotions they convey.