I am going to talk about Frege's view of truth. Frege divides every linguistic expression into two elements: sense and reference. Frege said that every linguistic expression can reach its reference through its sense. Consider the term 'dog'. The linguistic expression 'dog' is mediated by the sense of 'dog' to reach its reference real physical dogs. So far so good.
Frege said that senses of sentences are propositions and references of sentences are either the Truth or the False. This is very crucial. Propositions are meanings of sentences, which are expressed by formally correct languages, such as predicate logic. There are two things that follow: (1) Grasping a meaning of a sentence is the same as knowing a proposition of the sentence. (2) Knowing the truth/falsity of a sentence is only by the sense of the sentence, i.e. the proposition of the sentence.
Hope that helps.