Enabling Database Mail via TSQL

-- allow advanced options

sp_configure 'show advanced options', 1; 
GO 
RECONFIGURE; 
GO

-- enable database mail (0 disables , 1 enables)
 
sp_configure 'Database Mail XPs', 1; 
GO 
RECONFIGURE 
GO

-- hide advanced options again

sp_configure 'show advanced options', 0; 
GO 
RECONFIGURE; 
GO