What makes a fact true?

The question "what is truth" is something that philosophers have argued over for centuries. Many people believe in objective external reality, in which case a fact would be something that conformed to objective external reality (that is, anybody who viewed the same reality could rationally have only one true interpretation of it).

However, many philosophers argue that there is no such thing as an objective external reality - for example, by arguing that nothing exists outside of the human ability to perceive it. It is thus not possible for something to be "objectively" true. This is a controversial position but it remains popular.

Mathematicians often say that mathematics is independent of human reality, and therefore has objective standards of truth. But this is not accepted by everyone either.
I believe a fact is a statement that is true.