I have read up on [Digital signature](http://en.wikipedia.org/wiki/Digital_signature) and it is stated that it provides non-repudation. 

Assuming Alice signs the message using her private key and sends it to Bob, Bob can use Alice's public key to verify the signature hence Alice cannot deny sending the message. This only proves that Alice is the sender of the message. 

How can Alice have proof that Bob has received the message sent from Alice?