How does the embassy get to know the truth about.if one's married or not apart from the information provided on the DS -230 form. There's this friend of mine who won the DV-2014 but excluded his wife in both initial application and further processing due to financial constraints.
There's no right or wrong answer to this. If you conceal the truth then I guess they wouldn't know unless you had a previous record of US visas.
I am also divorced but I never wrote single on my forms purely because I did not want to take any chances and also because the US Embassy already has my previous US visits on record which include my marital status.
Your friend who excluded his wife in his application technically committed perjury/lied and what he did does not conform to the DV rules pertaining to transparency. Here's the question (financial constraints or not): is he going to the US alone or is he planning to take his wife with him? If he is going with his wife and if they ask for a marriage certificate (which they do) then your friend will be in trouble for not stating him being married on his application.
Just my opinion...
Case No - DV2013AF0007XXXX (applied the first time and got it the first time - lucky me!)
Entry Checked - 1st May 2012
Forms Sent To KCC - 10th May 2012
Received By KCC - 12th May 2012
Confirmation From KCC - 25th May 2012 after I sent them an email
2nd NL - 14th June 2013
Police Clearance (TZ) - 13th June 2013
Police Clearance (UK) - 21st June 2013
Medicals - Completed 24th June 2013
I-134 - 16th July 2013
Bank Statements - 22nd July 2013
Interview - Wednesday, August 7th 2013 @ 8am - US Embassy Tanzania
Visa Pick up - Hopefully August 11th 2013
Departure Date - August 17th 2013
Port of Entry - Washington Dulles