Translation:Han kommer til syne.
It's correct so don't worry you can say "han dukker op" in danish This website just really doesn't....
For some reason "dukke op" was introduced in a very similar sentence but for whatever reason wasn't added as an option for this sentence. I will add it now
"Han synes" would mean something like "He is of the opinion". "At komme til syne" actually means something like "he comes into sight", "he becomes visible" ==> "he appears". At least that's what I deduce from translating "syne" in Google Translate :) In Dutch we have a similar phrase, "in zicht komen".
As in 'an angel suddenly appears' or as in 'he shows up to work?' I put he shows up and got it wrong. Is that wrong or merely overlooked?
It is more comes into sight.