It is "bitter and sweet" but sounded out in katatana as "BITAA ANDO SUIITO" (ビター&スイート). It's the same with "endless play," which is written as "ENDORESU PUREI" (エンドレスプレイ). To be honest, I'm not sure about the ampersand in ビター&スイート. I romanized it as "ANDO" for "and." Sometimes it sounds like she's saying "wa," but that doesn't seem to fit the sentence.

as an addition to my previous response, that was just my opinion. so i don't really know if it's the right thing, it just really sounds like that :) but the kanji lyrics doesn't say that's what it says...haha.

i dunno if im right, but i thought the part where it said 'BITAA ANDO SUIITO' was just 'BITTER AND SWEET' and the english also said the same...

Okay, a clarification/correction of what I said before. There were a lot of word and word composition changes, all of which were wrong or unnecessary. Punctuation was also added, which violates the transliteration rules.

Not only did the dramatic changes in V5 of the Romaji section violate the transliteration rules, but most of the changes were wrong. I transliterated the lyrics straight from the kanji, not by ear (what I'm guessing was done here), so I'm 99% if not 100% sure what I had was right. Please don't make changes unless you're sure they're correct. Sorry if I sound rude. I was just a little surprised.