'However', 'nevertheless', and 'nonetheless' connect two sentences and show an unexpected result to what has been stated in the preceding sentence. 'However' is the most common of these expressions, whereas 'nevertheless' and 'nonetheless' are more formal are generally used in written English.
However, she decided to remain in Seattle to use the voucher.
However, the accountant decided to issue payments by means of a voucher.
Nevertheless, if we don't accept this loan, we won't be able to get our business up and running.
Nevertheless, if we are lazy at work the bank won't get the actual yield.
Nonetheless, the withholding tax was much more than I had expected.
Nonetheless, deregulation of the cigarette industry will not mean higher prices.