Y'ou can't just brand him a rapist on her say-so'
And so you have branded her a liar based on...? And before you retort with 'she told lies before' - are so squeaky clean that you have never told a lie? Does that now mean you are an outlaw and that anyone can commit a crime against you forever more and the law will shrug its shoulders?
Besides which:
(a) there is other evidence to support her version of events
and
(b) it is not a legal requirement for a rape convistion to have anything more than the victim's word. Whilst it is true that few such cases result in a conviction, it is entirely possible for a man to be convicted - as you so dismissively put it - on the victims 'say-so'