Also, had best. Ought to, should. For example, You had better finish this one before starting another, or We had best be going. [Mid-1400s] Also see you'd better believe it.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.