How do you know if you AirDrop something to someone?

How exactly do you ascertain whether an AirDrop has successfully reached its intended recipient? Is there a specific notification or confirmation message that appears on the sender's device? Additionally, does the recipient receive any indication that they have received the AirDropped content? Furthermore, are there any potential pitfalls or common issues that one should be aware of when utilizing the AirDrop feature? Could you elaborate on the reliability and security aspects of AirDrop, ensuring that sensitive data remains protected? Understanding these nuances would greatly enhance the user experience and ensure a smooth transfer of files.