'This is her' or 'This is she'?
His and hers are possessive pronouns. They are used to substitute a noun and to show possession or ownership.
Example: This hat is hers.
Note: We never use apostrophes with pronouns: 'Hers is black' is correct; not 'her’s is black'.
His and her are possessive adjectives; they usually describe a noun. They come before the noun.
Example: This is her hat
He and she are personal pronouns they are used instead of the man's or woman's name.
Example: Do you know Susan? She is my sister.
Note: She is the nominative form of the word, so it can not be used to describe somebody who is the object of a sentence. For example 'This is she' is not correct because 'this' is the subject. The correct sentence should be 'This is her'.
Himself and herself are reflexive pronouns they are used when the object of a sentence is the same as the subject: the person who does the action of the verb is the same person who receives the action
Example: She did it herself.
Link: What is a Relative Clause?
