Creating a pseudo email database
I would create "Status" as a lookup table 

SentStatus 
StatusId smallint identity (1,1)
StatusLabel char (10)


As it is easier to maintain and also add values to.

Of course, you should link "mail" to "Employer" and "Applicant" table using a many-to-many relationship.

Be mindful of over-using "var" if you don't need it, and definitely of the difference between nchar and char: if you know in advance that "status" is going to be a label in English which you assign, you don't need to accommodate for "nchar" which is double in length.