I'm having a really hard time understating the difference in sentences like—

Я был не уверен VS. Я не был уверен

Я не жил в Канаде VS. Я жил не в Канаде.

What is the difference in sentences such as the above mentioned? Thanks)

  • 2
    The first pair of sentences mean roughly the same: I wasn't sure / I was unsure. Apr 8, 2018 at 9:07
  • @SergeySlepov Which one is which? I was unsure = ?
    – VCH250
    Apr 8, 2018 at 11:26
  • 2
    "не уверен" is for unsure. However it typically requires a continuation, an added context. "я был не уверен в том и в том"
    – Arioch
    Apr 8, 2018 at 11:55

3 Answers 3


There is a subtle difference.

Я был не уверен VS. Я не был уверен
I was uncertain vs I was not certain. 
I was vs I was not

Я не жил в Канаде VS. Я жил не в Канаде.
I hadn't lived in Canada VS I lived outside of Canada.
Never lived in Canada vs Lived somewhere else at the time

Я не жил в Канаде

"I never lived in Canada"

Я жил не в Канаде

"I lived not in Canada (but in the United States)"

The latter implies some context. It is assumed that the narrator did live somewhere that could as well be Canada, but then they clarify that it wasn't Canada.


With regard to the first example...

In Я был не уверен не уверен in my opinion is ought to be written jointly неуверен and this construction is best construed as a complete statement, where неуверен completes the idea and ends the sentence. In it you describe your own state.

Я не был уверен on the other hand requires continuation, an explanation of what you were unsure of, which comes in the form of a subordinate sentence introduced with a conjunction что

Я не был уверен, что смогу успеть к назначенному времени

One can hear people say Я был не уверен, что... and although there may not be a strict rule against such use, in my opinion it's wrong stylistically.

Я не был уверен can also be a sentence in its own right if it follows a description of deliberation or hesitation

Смог бы я успеть к назначенному времени? Я не был уверен.

or a statement to which it is a comment

Он сказал, что погасит долг. Я не был уверен.

but it's a more bookish style unusual in everyday speech

Worth noting that in Russian unlike in modern English it would be incorrect to say

Я не был уверен, когда она придёт - I wasn't sure when she would come by

In Russian insufficiency of knowledge can't be expressed with the equivalent of the English unsure/not sure without sounding awkward.

Instead this idea is best conveyed with statements such as

Я точно не знал, когда она придёт

Я не знал, когда именно она придёт

  • не уверен is ought to be written jointly неуверен gramota.ru/slovari/dic/… - in contrast with full adjective неуверенный
    – Arioch
    Apr 8, 2018 at 14:18
  • quote (с дополн.: они не уверены в успехе), without complement (в успехе) it's ought to be written jointly Apr 8, 2018 at 15:53
  • "....краткое прилагательное пишется с не раздельно, если выражается отрицание, и слитно, если выражается утверждение и прилагательное заменяется синонимом: Он отнюдь не богат. Он небогат (беден)." - and here synonym is...?
    – Arioch
    Apr 9, 2018 at 8:12
  • synonym is сомневаюсь (it doesn't have to be an adjective, does it?), Rozental provides much more volatile rules Apr 9, 2018 at 8:17

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