However, this phrase is incomplete. It needs a verb following "se" to make a complete sentence.
For example:
* Ella no se va. (She is not leaving.)
* Ella no se siente bien. (She doesn't feel well.)
* Ella no se acuerda. (She doesn't remember.)
The "se" in this context usually indicates a reflexive pronoun, meaning the action of the verb is directed back to the subject (in this case, "ella").
To get a full understanding of the meaning, you need the verb that follows "se."