Juries decide whether the state or government has proved the charges beyond a reasonable doubt. If the state meets the burden, it returns a guilty verdict. If the state falls short in proving the charges beyond a reasonable doubt, it returns a verdict of not guilty. Those are the two choices.
A not guilty verdict can include:
** Based upon the evidence presented, we the Jury find that the defendant is absolutely 100% innocent.
** Based upon the evidence presented, we the Jury, cannot be absolutely sure that the defendant is innocent.
** Based upon the evidence presented, we the Jury are confident that the defendant is innocent.
** Based upon the evidence presented, we the Jury believe that the defendant is probably innocent. [More...]
** Based upon the evidence presented, we the Jury are not really sure one way or the other if the defendant is guilty or innocent.
** Based upon the evidence presented, we the Jury believe it is more likely than not that the defendant is guilty.
** Based upon the evidence presented, we the Jury believe that the defendant is probably guilty.
** We the Jury believe that the defendant is guilty but the evidence falls a little short and we cannot find that the defendant is guilty beyond a reasonable doubt.
For more on this see
The Meaning of a Not Guilty Verdict and
The History of the Presumption of Innocence