follow Dictionary.com

Get the details behind our redesign

You can be sure, as in Rest assured that the police will recover your diamonds. This expression uses assured in the sense of “certain” or “confident,” a usage dating from the early 1500s.
The American Heritage® Idioms Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Cite This Source

Word of The Day

Word Value for rest

4
4
Scrabble Words With Friends

Quotes with rest assured