I understand your answer .
I use to see my dates as follows :
meaning : 31 of July 2013.
1. Is Numbers can " see " this format as a TRUE date ?
If not , How can I change all dates to a TRUE formats when filing them into a cell ?
Meaning : When filling date , an automatic true format will be , instead of my false format ( Auto correction )
Numbers takes its 'all numeral' date format from the setting in System Preferences.
The setting is found in the Formats section of the International pane. If your preferred setting is available in one of the "Region" sets, use that.
Mine isn't, so as you'll see in the image below, I use a "Custom" region, as none of the pre-set regions fit (all) the formats I prefer.
Numbers doesn't handle this too well; it often flips the day and month when I change the format on an individual cell from 'Automatic" to Date and Time (eg. Jan 5, 2012 will change to May 1, 2012 if I re-format the cell), so I tend to avoid the 'all numeral' format where I can.