What is the the most profitable way of transferring euro to usd in the states. First answer it by bank transfer. I guess there would be a lot of fees. Another way i guess is through bitcoin since it is universal but i do not know how safe this is and how you can transform money credit to bitcoins and vice versa. Recently i read about stellar network which provices transactions in multi-currency system through gateways that receive credit in a currency and transform it in a stellar.
A currency broker will give you the closest rate to the interbank rate. Retail banks and money transfer companies take a spread (the difference between the interbank rate and the rate that they charge you) that is significantly higher than a broker. So search for a broker and get quotes for the amount you wish to transfer.
Have you tried TransferWise. They offer nice cross currency transfers with really low rates.