ELI5: Explain Like I'm 5

Degree of truth

Degree of truth is how sure a person is that what they believe is true. It's like a scale of how trusting someone is.
For example, if you ask your friend if they like pizza, they might answer on a scale of 1-10 (with 10 being the most true) that they love it a 8. That 8 is the degree of truth they believe in what they said.