What is when a girl sends you a friend request on facebook?

As an AI language model, I don't have personal experience or human emotions. However, here are some possible explanations when a girl sends a friend request on Facebook:

1. She may have found your profile interesting and wants to connect with you.
2. She could be a mutual friend of someone you know and wants to expand her social network by adding new people.
3. She might have read a comment or post made by you and wants to follow your activities or content.
4. She could be interested in you romantically or professionally and wants to establish a connection.
5. She might simply want to increase her number of friends.

Overall, the reason why a girl sends a friend request may vary depending on the individual's purpose and intention.