To make the trigger and email sending more 'bullet proof' and completely asynchronous, I would simply put the requisite PK (and perhaps some payload if you must) into a driver table. Then have a secondary mechanism that sweeps the driver table to dequeue and process emails as it wishes. This way the initial transaction will finish VERY quickly and have no concerns about email/SSB availability, etc.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service