No. Afrikaans is much simpler than English here.
In the present tense, you use is with all persons:
So unlike English, Afrikaans does not use different forms like am / is / are.
Because it comes after is.
In Die wyn is duur, duur is a predicate adjective. Predicate adjectives in Afrikaans normally stay in their basic form:
So there is no special ending here.
wyn is pronounced roughly like vain or vayn for an English speaker.
Two helpful points:
So wyn is definitely not pronounced like English win.