Use appropriate account for sql agent to get access to mail system and then:
How to set up SQL Mail (Enterprise Manager)
To set up SQL Mail
Expand a server group, and then expand a server.
Expand Support Services, right-click SQL Mail, and then click Properties.
In the Profile name list, type or select the mail profile that you configured for SQL Mail.
Click Test to check the ability of the system to start and stop mail client services with the profile entered.
You should receive a message that SQL Mail has started successfully and stopped a mail session with this profile.