i'm stalking a pair on ebay which are not my size, but i asked the seller to take inside measurements for me and from her measurements they should fit perfectly.
I find they run true to size maybe slightly small. I am always a size 6 shoe and a 36 european and that is what fits. I would make sure the seller gave you the european size not his/her conversion. I find there are different conversions. Some stores label a 36 as a size 5 etc, but I don't find that to be true. HTH
it's quite odd though. the seller has a pair that is listed as size 6, european size 36. i'm normally a 7 (37) or 7.5 (37.5) but the measurements she gave me seem like they would fit perfectly. either the pair is mismarked the wrong size OR she has measured wrong.
either way, i trust my ST girls for accurate info. i'm gonna say they won't fit me if they are a size too small.