Hearsay is a statement that’s
Example: John tells Bob that he saw Steve rob someone. At Steve’s trial, the prosecutor asks Bob to repeat what John told him. The statement that John saw Steve rob the victim is being offered to prove that John did in fact see Steve commit the robbery. So, it’s hearsay.
Example: Alfred is defending against an assault charge on the theory that he acted in self-defense against Nigel, the alleged victim. He claims that Nigel attacked him. In order to prove that Nigel wouldn’t have attacked Alfred, the prosecutor asks Oliver to repeat what Nigel had previously said about Alfred. Oliver responds, “Nigel told me that Alfred always carries a large knife that he’s very adept with.” Oliver’s testimony is not hearsay. The prosecutor isn’t offering it in order to prove that Alfred actually did carry such a knife and that he knew how to handle it. Instead, the testimony is relevant to show Nigel’s state of mind: that he believed that Alfred carried and knew how to use the knife. If he believed that, the theory goes, then he would have been unlikely to attack Alfred.
(For more on the hearsay concept, including exceptions, see Hearsay in Criminal Cases.)