Most people spell 지민이 either Jiminie or Jiminy (probably because that's what you'd add to the end in English), but I spell it Jimini.

There's 2 reasons, really.

1. because his name is 지민.
ㅈ = j/ch
ㅣ = i
ㅁ = m
ㅣ = i
ㄴ = n

That's the technical romanization of those characters.

Then, when you add the cute ending to it, the name becomes 지민이
지 = ji
민 = min
이 = i  (the ㅇ is silent because in Hangul, all blocks [which are syllables] start with a consonant, and the second "letter" in it is always a vowel.  Okay, well some blocks don't start with a consonant, but instead start with the silent placeholder 'ㅇ.'  Without the silent placeholder, his name would end up like 지미니, ji-mi-ni.  But that's wrong.  It's ji-min-i)

me:

you:

Just trust me on this, okay?

2. because he's mini-sized.  He's jiMINI-sized!  Do you see it?  Jimini Get it?  Huh?  Do ya? HAHHAHAHA I'm funny.