She is truly a, no THE winner.
I am having trouble deciding if this punctuation is correct, or whether it should be:
She is truly a, no THE, winner.
She is truly a, no THE winner.
I am having trouble deciding if this punctuation is correct, or whether it should be:
She is truly a, no THE, winner.
One principle of contemporary punctuation is to insert commas, semi-colons, colons and full stops/periods to indicate the position and length of pauses in speech. Em-dashes can be used to indicate an interruption or aside.
So to answer your own question you need to speak the sentence out loud, and then apply your principles.
To some extent, then, this becomes a question of individual diction and one’s opinion on how much one should punctuate. I personally would use em-dashes to indicate (self-) interruption, together with perhaps† a comma to indicate the pause after ‘no’:
She is truly a — no, the — winner.
Another question is how to emphasize ‘the’. Italics are more usual than upper case in printed work, as they provide sufficient emphasis without appearing to ‘shout’ or spoil the look of the page. (Bold is also better avoided — see the effect above.) This may also depend upon house style.
† The comma could be omitted, especially as ‘the’ is italicized. I included it to show the scope for punctuation within the interruption. It also makes the sentence look rather cluttered here.