How do you avoid an embarring encounter with someone you professed undying love for and were shot down?

Tiny smile. One nod in their direction and then eyes down keep walking. If he wants to talk he will say something. If he is negative your eyes are down and you can just keep walking. If he sounds pleasent then your eyes can always come back up as a sign that you are listerning. Time will heal your wounds just don't let fear overpower you.