In general, such persons could be called believers.
Usually, a doubting Thomas, (Biblical)
Nihilist
A person who believes that war is wrong is called a "pacifist".
Christian??
A person who believes in their dreams can be referred to as a dreamer or an idealist.
A statement that tells what a person thinks or believes is called an opinion, sometimes known as a belief.it is known as a belief
Pacifist
This is called an opinion.
They are called an Anarchist.
Contrapositive
Agnostic
Gullible: Easily persuaded to believe something