I nursed it in my bosom while it lived,
 I hid it in my heart when it was dead;
In joy I sat alone, even so I grieved
 Alone and nothing said.
I shut the door to face the naked truth,
 I stood alone,--I faced the truth alone,
Stripped bare of self-regard or forms or ruth
 Till first and last were shown.
I took the perfect balances and weighed;
 No shaking of my hand disturbed the poise;
Weighed, found it wanting: not a word I said,
 But silent made my choice.
None know the choice I made; I make it still.
 None know the choice I made and broke my heart,
Breaking mine idol: I have braced my will
 Once, chosen for once my part.
The two phrases are syntactically reversed, a device known as  chiasmus . The construction creates sonority, to add to the sense of rightness of her choice.
Memory