Sure

Sûre or Sauer , principal river of Luxembourg, c.100 mi (160 km) long, rising in the Ardennes, SE Belgium. It flows east through Luxembourg, then south (forming part of the Luxembourg-German border) to join with the Moselle (Mosel) River. With its tributaries, the Our, the Clerf, and the Alzette (which passes through the city of Luxembourg), the Sûre drains all of Luxembourg.

sure †safe, secure XIV–XVII; trustworthy, steadfast XIV; subjectively certain XIV; objectively certain XV. — OF. sur(e) (mod. sûr) :- L. sēcūrus SECURE.
So surety †safety, security, certainty; bond entered into for the performance of an undertaking XIV; person undertaking this, bail XV. — OF. surte (mod. sûreté) :- L. sēcuritās, -tät- SECURITY; see -TY2. Whence suretyship XVI.

sure / shoŏr/ • adj. confident in what one thinks or knows; having no doubt that one is right: I'm sure I've seen that dress before she had to check her diary to be sure of the day of the week. ∎  (sure of) having a certain prospect or confident anticipation of: Ripken can be sure of a place in the Hall of Fame. ∎  certain to do something: it's sure to rain before morning. ∎  true beyond any doubt: what is sure is that learning is a complex business. ∎  able to be relied on or trusted: her neck was red—a sure sign of agitation. ∎  confident; assured: the drawings impress by their sure sense of rhythm. • adv. inf. certainly (used for emphasis): Texas sure was a great place to grow up. ∎  [as interj.] used to show assent: “Are you serious?” “Sure.” PHRASES: be sure do not fail (used to emphasize an invitation or instruction): be sure to drop by | be sure that you know what is required. for sure inf. without doubt: I can't say for sure what George really wanted. make sure establish that something is definitely so; confirm: go and make sure she's all right. ∎  ensure that something is done or happens: he made sure that his sons were well educated. sure enough inf. used to introduce a statement that confirms something previously predicted: when X-rays were taken, sure enough, there was the needle. sure of oneself very confident of one's own abilities or views: he's very sure of himself. sure thing inf. a certainty. ∎  [as interj.] certainly; of course: “Can I watch?” “Sure thing.” to be sure used to concede the truth of something that conflicts with another point that one wishes to make: the ski runs are very limited, to be sure, but excellent for beginners. ∎  used for emphasis: what an extraordinary woman she was, to be sure. DERIVATIVES: sure·ness n. ORIGIN: Middle English: from Old French sur, from Latin securus ‘free from care.’