Yourself vs Yourselves( +Your Self)? What is the difference?

Yourself is correct and a reflexive pronoun in English. Yourselves can only be used when you are using “you” in the plural. Your self is used in another context. 

You need to bake the cake yourself.

Yourself

Yourself is the reflexive pronoun for the pronoun “you”. We use a pronoun in place of a noun when we don’t want to state the noun. A reflexive pronoun is when the pronoun is both the subject and the object of the sentence. This happens for example when the person(or people) is both the doer and receiver of an action. 

You have to cut the grass yourself. We had no gardener. 

Yourselves

Yourselves is also correct in English. The pronoun “you” can be both singular and plural in English. We use “yourself” when “you” is one person and “yourselves” when “you” is a group of people.

You need to clean the garage by yourself. (talking to one person)

You need to clean the garage by yourselves. (talking to more than one person)

You can imagine the situation when a parent is talking to one child or two. 

Your self

“Your self” is not used as a reflexive pronoun but can be used in another context. “Self” is a noun that means a person’s essential being. In this case, you can use “your self”

Your self has many layers.

Conor