This summary is not the rule. The rule text controls.
Hearsay is when someone testifies about a statement made outside of court, and that statement is being used to prove that what it says is true. For example, if a witness says "my neighbor told me she saw the defendant at the store," and this is used to prove the defendant was actually at the store, that's hearsay.
This rule says hearsay generally cannot be used as evidence in court. The main reason is fairness. The person who originally made the statement isn't in court to be questioned about it. The other side can't ask them what they really meant, whether they were being honest, or whether they made a mistake.
There are many exceptions to this rule, and those exceptions are found in other parts of the evidence rules. Things like statements made under stress, business records, or certain statements by an opposing party can sometimes be allowed in, even though they are technically hearsay. So while the basic rule blocks hearsay, it's really just the starting point. Whether a specific statement gets in often depends on whether it fits into one of those exceptions.
