San Francisco tops the list; Brownsville, Texas, comes in last
                                
                                
                                    (Newser) -
                                    Getting hit with Cupid's arrow is "part willingness and part geography," notes  WalletHub . And with 109 million or so single adults in the US as of 2015, per the latest  census , finding the right place to settle down in both the geographical and romantic sense can be...