Solemn
Synonyms: earnest, grave, in earnest, sedate, sincere, sober

Definition:
   1. Dignified and somber in manner or character and committed to keeping promises
"a solemn promise"; "the judge was solemn as he pronounced sentence"
   2. Characterized by a firm and humorless belief in the validity of your opinions
"a film with a solemn social message"

Passage:
       
On Tuesday morning, September 11, 2001, terrorists attacked America in a series of despicable acts of war. They hijacked four passenger jets, crashed two of them into the World Trade Centre's twin towers and a third into the Headquarters of the U.S. Department of Defence at the Pentagon, causing great loss of life and tremendous damage. The fourth plane crashed in the Pennsylvania countryside, killing all on board but falling well short of its intended target apparently because of the heroic efforts of passengers on board. This carnage, which caused the collapse of both Trade Centre towers and the destruction of part of the Pentagon, killed more than 250 airplane passengers and thousands more on the ground.
       Civilized people around the world denounce the evildoers who devised and executed these terrible attacks. Justice demands that those who helped or harboured the terrorists be punished -- and punished severely. The enormity of their evil demands it. We will use all the resources of the United States and our cooperating friends and allies to pursue those responsible for this evil, until justice is done.
                             - President George W. Bush (September 13th 2001)
Explanation: In this speech, President Bush uses a solemn tone. He does this by describing an event that was very hurtful and horrific to the audience in a serious and a sincere manner and by creating passing using relatively noncomplex sentences. Bush uses strong negative words and word phrases such as “despicable,” “great loss of life,”  “killing,” and “destruction” to show his real feelings for the terrorist actions, thus creating a sincere tone. Bush also uses noncomplex declarative sentences with intent of a pause after each one. This creates the slow, serious and sincere sounding pacing, which creates a serious tone. Combinations of the sincere tone created by the negative word phrases and the serious and sincere tone created by the pacing, creates the overall solemn tone. President Bush uses this tone to empathize with the nation and to reassure the American people that things will be O.K. in the future.