I just learn Mandarin from songs whenever I find the time. I have recently discovered this JC's song called Shuo San Jiu San. In the last sentence of the last paragraph of the song, which goes"因為成長 我們忽爾間說散就散", I understand most of the characters' meanings except 忽爾間. Google translate says "time flies" but I don't think that's the case. My personal translation of that line would be " because we have all grown up, let's break up if you say break up". I have no idea where that 忽爾間 would interact with other characters.
I think it is more common to say 忽然间 than 忽尔间，but it is a song!
忽然间他看见了我,就往回走, 伸出手来. Suddenly he saw me, and walked towards me, holding out his hand.
因為成長, 我們忽爾間說散就散 Because (we had) grown, changed, we suddenly said break up then broke up.
There is also 忽而 。。。 忽而，but that is a different kettle of fish!
Adding to my comments from yesterday, here in a proper post.
I looked at a couple of sources online, to confirm a few things. Funnily enough, when I Google searched "忽爾間", Google gave me the translation as well as links related to the song "說散就散".
https://tw.ichacha.net/hy/%E5%BF%BD%E7%88%BE.html http://chengyu.game2.tw/archives/188440#.Wpl6RWrwaM8 ^ to confirm the meaning of 忽爾. Looks to be a rather archaic way to say "all of a sudden". It means 忽然、突然, and both of these are the more common terms used today.
I like this link here as it does a great job of dissecting the meaning of the song lyrics, imo. Here, the author explains well the song lyrics are well-written, and how the build up of the lyrics accumulated to its last line:
In context, the translation to "我們忽爾間說散就散" would be: We broke up out of the blue.
Throughout the song, the singer is the voice of a woman trying to make sense of a relationship that ended abruptly by the other party.
The beginning of the song sounds like the goodbye hug one may receive if the relationship is ended in person. She's thinking back to what could have gone wrong, she had put so much into the relationship and lost sight of her identity, but even so, was it one-sided all along? Was it still not enough?
We see her replaying the events and really, feeling hurt that she was dumped even though she did nothing wrong, as evidenced by how the following two lines are repeated: 說不上愛別說謊 就一點喜歡 說不上恨別糾纏 別裝作感嘆
The following lines belong together. It's how the woman is choosing to move forward with her life; she accepts what has happened, no one did anything wrong, it's just they've grown apart, and so the relationship has ended out of the blue. 將一切都體諒 將一切都原諒 我嘗試找答案 而答案很簡單 簡單得很遺憾 因為成長 我們逼不得已要習慣 因為成長 我們忽爾間說散就散
My interpretation of course, after listening to the song on repeat as I write this post.