Perseverance
In Wendy’s eyes, Dan was not a serious guy and she was not going to let her heart be broken again, so she decided not to reply. Dan would not give up that easily and decided to try messaging again a couple of weeks later.
Wendy had clearly ignored him, so why he would try again? Out of curiosity, she decided to check his profile. She then saw that they both had a large list of mutual friends, and decided to reply, starting an online friendship.