That's not strictly true is it, this is the actual quote
That's not him confirming he'll be at the club that's him just giving a vague answer to please the fans. After losing Flamini on a free Arsenal would be insane not to sell Nasri when he's made it clear he wants to move thus making the chances of him signing a new contract slim unless he has a complete change of heart
Or the first bit
Wenger said:“I expect Samir Nasri to stay. There is always speculation, but he is committed to the club right now.’
Flamini is a total different situation. He was about to sign for Birmingham fpr £3m for first team football, the move broke down, he stayed, and then got it at Arsenal, and didn't sign a new deal.