Well I’m sorry but that’s a pretty basic part of the human experience. While there are some situation in which one can be blunt and straightforward, other situations require all the tact and empathy you can muster… Imagine turning someone down for a job interview. If the person cared for this job, every single word you say will be taken very personal and be mulled over afterwords. That means it is up to you to pick your words very carefully, and find a constructive phrasing.