why does it take so long for bitcoins being received to be Confirmed?
A transaction is confirmed once a miner includes it in a block
Most transactions confirm fairly quickly, entering either the next block or the one right after, and then from there confirming within an hour when the six confirming block is hit.
Other transactions are not included by miners right away -- perhaps they are low priority because they look like spam, or there was no transaction fee paid, or the coin was new (had been used in a transaction shortly before being sent to you). Adding a fee, just above the minimum even, generally will put your transactions in the front of the line.
At any point in time there are hundreds, sometimes thousands, of transactions that have not yet been included in a block:
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http://blockchain.info/unconfirmed-transactionsi have an offline wallet with perfect connection
If you have an offline wallet that means it is kept offline, and thus not connected. Did you mean something else?