Dumbledore's Trust of Snape

[bohcoo]

No: HPFGUIDX 80570

A possible explanation for Dumbledore's unshakable trust in Snape:

After The Prank Snape didn't tell anyone that Lupin is a werewolf 
because he gave his word to Dumbledore he wouldn't.

That had to be one of the hardest things a 16-year old boy could be 
asked to do:  Don't destroy another kid who belonged to a group of 
boys who had taunted and humiliated him continually for the previous 
4-5 years, in front of the entire school. Keep secret the one thing 
that would be guaranteed to completely ruin Lupin's life. What 
awesome sweet revenge that would have been. But. Snape kept silent. 
Snape kept his word to Dumbledore.

So, then, later Snape joins the Death Eaters but has a change of 
heart and goes to Dumbledore to offer his spy services to the Order 
of Phoenix. Having proven himself to be a man of his word to 
Dumbledore in the past, under possibly the most gut-wrenchingly 
tempting circumstances imaginable, Dumbledore continues to trust him.

I know I would.

Bohcoo