I guess the way other things get corrupted like Saint Nicholas became Santa Claus.
Europeans would pronounce Saint like SANTit's weird.

It isn't pronounced Sin Jin, it is pronounced Sinjon and I've heard it plenty of times in reference to a person's name, not the saint.

Sin Jin is the way they pronounce Saint John in the UK,
I am from the UK and have lived here for all 43 years of my life and have never heard anyone pronounce Saint John as SinJIn St John is pronounced Saint John
There's no point of being grown up if you can't be childish sometimes.

Sin Jin is the way they pronounce Saint John in the UK
Thanks for the info. That would make sense if either the show or the character were British.
Ignoring politics doesn't mean politics will ignore you.
-Pericles paraphrased in <100 characters

FYI, if you watch any of the British versions of "Jane Eyre" you'll hear the name of the character St. John Rivers pronounced that way.

Sin Jin is the way they pronounce Saint John in the UK, and it carried over here. As an aside, it was a stupid name to pin on Kanye West's new son, both for teasing reasons and for the implication that Kanye named the kid so because he thinks he's a god. Just sayin'