A possible translation may be:
1. Veni, vidi, sed vincere non potui.
2. Veni, vidi, num vincere potui? *
* num implies a negative answer only, it doesn't express a doubt.
Exactly. Something like 'how could I possibly win?'So do you mean the answer to the second translation will be a no?
I'd suggest to divide the sentence in two parts:is there a way I can ask it as a question?
So i will write this because im not sure i understand correct so;I'd suggest to divide the sentence in two parts:
Veni et vidi. Vincere potui? or Vincere poteram?
vincere potui? = have I actually conquered? (after the event)
vincere poteram? = was I capable of conquering? (before the event)