When the ????? is with someone it doesn’t let him sin. So, unless the person went sour it can’t be that he fell upon such a sin.
The ???”? explains that since this was the only reason he didn’t sin it was counted as if he did. He gives an example of someone about to steal from you and since you don’t want him to be ???? the ??? of ????? you are ????? the object. Now, the only reason you were ????? the object was because of the impending ?????. Therefore it’s not as if it never took place. Had the case been that he tried to sneak in and steal but found everything locked, that would indeed be as if it never happened, since it never came to fruition. (Similar to the ???? of ????? ???? ????. )