To address what you have been told: Emma Sansom did not "fight" in the war. Her participation was limited to one day, May 2, 1863, when she directed Confederate General Nathan Bedford Forrest to a stream crossing near her home which was near Gadsden, Alabama.
Coincidentally, Captain Enoch Vandiver, Co. A, 26th Alabama Infantry (O'Neal's), was in Virginia on that same day, participating in the Battle of Chancellorsville where he was wounded on either May 2 or May 3, 1863. This information comes directly from his records. So you see, any connection between the two of them is highly unlikely, at least during the war.
What information do you have that Captain Vandiver was your ancestor?