Prediction: Dumbledore's trust in Snape
I it my belief and prediction that the reason Dumbledore trusts Snape is because Snape was left distraught when he found out the information he passed to Voldemort would lead to Lily's death.
Evidence or Support
This is the big question - but why would Snape put his neck on the line for someone he hated and his wife who he considered a mudblood.
I think the reason Dumbledore trust Snape is because Snape is doing all he can to help Dumbledore/Harry fight Voldemort and passing information that is making it possible for them to better prepare.
Dumbledore trusts him because he knows that Snape would never have wanted to see Lily die and now she is - he wants to redeem himself.
I it my belief and prediction that the reason Dumbledore trusts Snape is because Snape was left distraught when he found out the information he passed to Voldemort would lead to Lily's death.
Evidence or Support
This is the big question - but why would Snape put his neck on the line for someone he hated and his wife who he considered a mudblood.
I think the reason Dumbledore trust Snape is because Snape is doing all he can to help Dumbledore/Harry fight Voldemort and passing information that is making it possible for them to better prepare.
Dumbledore trusts him because he knows that Snape would never have wanted to see Lily die and now she is - he wants to redeem himself.