Reading the poem, we encounter ourselves with “Success in Circuit”. As you see Dickinson has capitalized the words success and circuit. Now, you wonder why they have been capitalized and THAT is the for the reason, to give it emphasis, in other words giving life to these two words. Because the sentence is talking about success inside of lines, inside of the truth YOU tell. We need knowledge about the truth, because it’s the only way to Success and Circuit.
Now for the punctuation which is put in the first line “Tell all the truth but tell it slant -” the dash is put afterwards “tell it slant” to give it a feeling as
if this is a serious matter. It’s basically saying “I don’t play”. YOU need to tell it how it is. Not in the direction of him or her but, in your matter. The way YOU view it.