what are the japanese kanji symbols for the word sweet and the letter j?

Answer 1

In katakana / hiragana;
ja = ジャ　／　じゃ
ji = ジ　／　じ
ju = ジュ　／　じゅ
je = ジェ　／　じぇ
jo = ジョ　／　じょ

Although, literally speaking, if you just want the phonetic representation of the letter 'j' as it's spoken, I suppose you should use 'ジェイ'!

There is no representation of the letters of our alphabet, only phonetics like those above. Katakana is used mainly for foreign words, and hiragana is mainly used for pronunciation of kanji, and for particles. They used to use kanji before katakana was invented, but as each kanji has so many possible pronunciations, and there are many different kanji that can be used to represent the same thing, you'll be lucky to find anyone on here who knows ALL of them ... and is willing to write them down for you! If you want to write your name or something in kanji, the best way is to use a Japanese dictionary that searches for kanji by their pronunciation. Note a few different kanji, and their MEANINGS, and try to use a selection of kanji that doesn't have an offensive or ridiculous meaning...!! (You might be surprised how many people slip up in that respect..!)

Dictionaries where you can search -
This one is only useful if you can type Japanese characters on your computer, but it has the largest database of kanji I've found online so far;
http://www.csse.monash.edu.au/~jwb/cgi-bin/wwwjdic.cgi?1C

This site only accepts Latin (English) characters;
http://rut.org/cgi-bin/j-e/dict
(It's working ATM, but often it's down for some mysterious reason.)
You select the meaning you like from your search results, click on the romaji word and see the kanji. (Settings for colours and sizes of the kanji can be altered on the main page that I've given you.)

This site accepts Latin letters or Japanese characters;
http://www.yesjapan.com/dictionary/yesjapan200k.php

As for the word sweet, it depends on the context. Go here,
http://www.yesjapan.com/dictionary/yesjapan200k.php?language=english&searchplace=containing&searchfor=sweet&go=Search%21&maxsearch=100
and take your pick..!
; )

Answer 2

As you might know, japanese writting is composed of three kind of symbols: kanji, katakana and hiragana. Kanji represent full ideas.
I do not remember the kanji for sweet, but I can tell you that letters are not represented by kanjis the way you understand it.
Instead of letters, they use two silabic systems named katakana and hiragana. Both systems have the silabics "ja" "ji" "ju" "je" and "jo", represented by special symbols, hiragana is used for japanese native words, katakana is used for non japanese native words. None of such symbols are kanjis at all.
However, some japanese uses the romanic letter "j" in some context such as: J-pop to designate the japanese pop music. (They call it roma-ji writting)

Answer 3

甘い <- this means sweet/ u pronounce it "ah-ma-i"

ja = ざ,じゃ(hiragana)
ザ.ジャ(katagana)
ji =,じ(hiragana) ,
ジ(katagana)
ju = じゅず(hiragana)
ジュ,ズ(katagana)
je = ぜ(hiragana)
ゼ(katagana)
jo = じょぞ(hiragana)
ジョ　ゾ(katagana)