Sweet nothings are words exchanged between two lovers and usually portrayed in stories after an intimate scene or sometimes when two lovers are reunited. In a personal opinion, I believe they fall under simple things like "You'll never know how much I truly love you." Or "You're my best dream to come true."
whispered words into your lover's ear in hopes of arousing sexual stimulation; try whispering a few naughty or suggestive phrases; often it doesnt even matter what you say as long as you say it in a sexy way