Believe (verb)

1. To accept as true or real.
2. To have faith or trust in something or someone.
3. To have a strong conviction or opinion about something.
4. To consider to be probable or likely.
5. To have confidence in the existence or reliability of something.

Origin:

Derived from old english 'believan' meaning 'to hold dear'.

Examples:

1. I believe in God.
2. She believes in love.
3. He believes in aliens.
4. I believe that he is coming.
5. We believe in the project.