Voldemort's defeat

[puju02]

No: HPFGUIDX 94246

Puja:
JKR often hints at Harry's defeat. However in PS she shows LV 
drinking unicorn blood (thru Prof. Quirrel). Drinking unicorn blood 
gives the person "a half life, a cursed life". Does this imply that 
LV will definitely be defeated or did that refer to Prof Quirrel 
having a half and cursed life because he was the one drinking unicorn 
blood. Just looking for excuses for Harry not to die....