资料来源 : pyDict

的确,无疑,诚然,不错

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Sure \Sure\, a. [Compar. {Surer}; superl. {Surest}.] [OE. sur,
   OF. se["u]r, F. s[^u]r, L. securus; se aside, without + cura
   care. See {Secure}, and cf. {Assure}, {Insure}, {Sicker}
   sure.]
   1. Certainly knowing and believing; confident beyond doubt;
      implicity trusting; unquestioning; positive.

            We are sure that the judgment of God is according to
            truth against them which commit such things. --Rom.
                                                  ii. 2.

            I'm sure care 's an enemy of life.    --Shak.

   2. Certain to find or retain; as, to be sure of game; to be
      sure of success; to be sure of life or health.

   3. Fit or worthy to be depended on; certain not to fail or
      disappoint expectation; unfailing; strong; permanent;
      enduring. ``His sure word.'' --Keble.

            The Lord will certainly make my lord a sure house;
            because my lord fighteth the battles of the Lord.
                                                  --1 Sam. xxv.
                                                  28.

            The testimony of the Lord is sure.    --Ps. xix. 7.

            Which put in good sure leather sacks. --Chapman.

   4. Betrothed; engaged to marry. [Obs.]

            The king was sure to Dame Elizabeth Lucy, and her
            husband before God.                   --Sir T. More.

            I presume . . . that you had been sure as fast as
            faith could bind you, man and wife.   --Brome.

   5. Free from danger; safe; secure.

            Fear not; the forest is not three leagues off; If we
            recover that we are sure enough.      --Shak.
      

   {To be sure}, or {Be sure}, certainly; without doubt; as,
      Shall you do? To be sure I shall.

   {To make sure}.
      (a) To make certain; to secure so that there can be no
          failure of the purpose or object. ``Make Cato sure.''
          --Addison. ``A peace can not fail, provided we make
          sure of Spain.'' --Sir W. Temple.
      (b) To betroth. [Obs.]

                She that's made sure to him she loves not well.
                                                  --Cotgrave.

   Syn: Certain; unfailing; infallible; safe; firm; permanent;
        steady; stable; strong; secure; indisputable; confident;
        positive.

资料来源 : WordNet®

to be sure
     adv : admittedly; "to be sure, he is no Einstein" [syn: {without
           doubt}, {no doubt}]