Is the middle "n" silent? Am I just not used to hearing it and can't identify it?
The duolingo pronunciation sounds like "zein" https://www.duolingo.com/dictionary/Japanese/%E5%85%A8%E5%93%A1/46748a7b24925ca8284f992c47fdfa40
The two femails pronounce it as "zenin" while the male and AI pronounce it "zein" - https://forvo.com/word/%E5%85%A8%E5%93%A1/
The hiragana spelling I got is from https://en.wiktionary.org/wiki/%E5%85%A8%E5%93%A1