How can we assign a user , e.g.: the database owner (DBO) the UNSAFE ASSEMBLY permission?
I'm asking it to enable a user to create an assembly and don't know the SA password, so
EXEC sp_changedbowner ‘sa’ can't help.
Only users mapped to a login that's a member of the sysadmin fixed server role can create and alter an assembly with an UNSAFE permission set defined. Therefore, to achieve your desired result you would have to add that respective login to the sysadmin fixed server role.