Hello All, Im looking at a pair of ysl boots on ebay, from I guess a few seasons ago? It is a 39. It says it fits more like an 8. I only own one designer pair of shoes and it is marc jacobs misplaced heel and it was a 37. generally speaking i wear a 7.5. I have a very narrow foot. I can also wear an 8. I know nothing of YSL fit, and have read varying answers. can someone let me know what they think? and also authenticate in the authenticate thread? They dont seem like a pair of shoes that would be counterfeited.