The evidence was obviously strong enough for a court to decide in his favour. Generally you have to prove that something happened in order for a court to do that.
You can’t assume that. This article doesn’t say. It’s possible that there’s no evidence other than this one man’s word. Look at the Cardinal Pell case in Australia. Pell was convicted based on the absurd, extraordinarily unlikely testimony on one accuser... yet a jury bought it... and so did 2 out 3 judges on the initial appeal.