The statement that INCORRECTLY describes intensive pronouns is, "They are surrounded by commas to set them apart from the sentence."
An intensive pronoun is similar to a reflexive prounoun in that it ends in self or selves (myself, himself, themselves, etc...). They are used to create emphasis and can be removed from the sentence without affecting the meaning. They generally, but don't always have to, follow immediately after the noun. Look at the example.
"Bianca herself knew better even if Lina did not."