According to Wiktionary it's /fʁɑ̃.sɛ/. So like the English word "set" without the -t. Even including an "n" is not correct; it nasalizes the vowel. This is why English-like transcriptions can only take you so far. There's only so many sounds in English, and when languages start using ones that don't exist, it's impossible to bridge that gap.

As a monolingual English speaker until college, I have had a terrible time with distinguishing some word-final diphthongs. For instance, I catch myself using the English "-o" /oʊ/ in Spanish, when it should be just /o/. I also have a hard time with /e/ vs /eɪ/.