First of all, if at all possible, don't fire someone in an email. Second, I'm not a particularly blunt person, but I'm not sure the sandwich approach works here

First of all, if at all possible, don't fire someone in an email. Second, I'm not a particularly blunt person, but I'm not sure the sandwich approach works here. It's great if you have the opportunity to help the person being let go find new employment. However, it's important to ensure the person is clear that it's not working out and there's no room for negotiation. (And there shouldn't be by the time you've made the decision to fire someone.)