matter-of-fact
Calm, plain, and direct, without extra emotion or drama.
Matter-of-fact describes a way of speaking or behaving that is straightforward and unemotional, sticking to plain facts without drama or exaggeration. When your doctor explains in a matter-of-fact tone that you've broken your arm and will need a cast for six weeks, she's being direct and calm, treating it as a simple reality rather than making it seem scary or overly serious.
Someone with a matter-of-fact manner doesn't add unnecessary emotion to situations. If your friend announces in a matter-of-fact voice that she forgot her lunch, she's just stating what happened without making a big deal about it. This doesn't mean the person is cold or uncaring. Rather, they focus on what is instead of adding feelings that might cloud the situation.
The phrase works as both an adjective and an adverb. You might describe someone's matter-of-fact approach to problem-solving, or say that they explained something matter-of-factly. Scientists often write in a matter-of-fact style, presenting their findings clearly without dramatic language. A matter-of-fact attitude can be especially helpful in emergencies, when staying calm and focusing on facts helps everyone know exactly what to do next.