Marriage certificate in vietnam is very quick for mine in June 2012 in Ben Tre. Took like 2 weeks. We had to have a brief interview before the certificate, but was very easy. Your lawyer in vietnam is trying to scam you, dont trust lawyerss in VN, they are all crooks. You do need a single status declaration and a medical examination, they want to know that you are mentally sane to marry, Lol, no joke. I had to do all these stuffs. The single status declaration takes a month or so to do here in canada. I had a viet travel agency help do mine for about $500 or so, could be less, i forgot. Also ask notary public agencies. Good luck.