Tempting You to Stay. It's a reaction that's both good and bad: Your boss values you so much that he or she offers you a raise or promotion to stay. But it can leave you feeling conflicted: You have another great job lined up__but now that there's more money on the table, do you really want to leave your current position?
Even if you're not close with your boss, chances are you have a working, first_name_basis relationship. Maintaining that in your official letter is okay. You don't need to keep a Victorian level of formality here__just make sure it's a professional tone.