Robin was sure to have done the work.

Who was sure? Was it Robin? Or was it another person who was sure that Robin had completed the work? If this was Robin, why would someone write the following sentence to say that Robin was sure?

Robin was sure that he had done the work.

  • 1
    How would the first sentence be referring to another person? "he" in the second sentence could refer to Robin himself or another person that Robin thought about him getting the work done. Commented Dec 6, 2015 at 7:28
  • I thought the first one is passive construction.
    – user17969
    Commented Dec 6, 2015 at 7:58
  • 2
    I guess you took the sentence from this Wordreference discussion Commented Dec 6, 2015 at 9:43
  • With its full context the meaning would be understood. Sentences can mean different things according to the situation and who is speaking. Real life is not made up of isolated phrases on whose meaning we ponder for hours on end, consider the following ambiguous phrase: She ran towards the display, her nose pressed against the glass.
    – Mari-Lou A
    Commented Dec 7, 2015 at 19:40

1 Answer 1


This isn't the same meaning of sure that you're thinking of. "I'm sure that" is roughly synonymous with "I am convinced that", but "I'm sure to" is closer to "I definitely would".

Robin definitely would have done the work.

Your second sentence means this:

Robin is convinced that he had done the work.

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