Final answer:
The phrase that expresses calmness is Estoy tranquilo.
Step-by-step explanation:
The phrase that expresses calmness is Estoy tranquilo. In Spanish, the verb estar is used to describe temporary states or feelings. Tranquilo means calm or relaxed. So, the phrase Estoy tranquilo translates to I am calm or I am relaxed.
Learn more about Expressing calmness in Spanish