Loved by some, hated (or rather despised) by others, truth is that they do have some beautiful songs. This is probably their best one (to my taste).

karaoke version: I WANT IT THAT WAY -karaoke

Yeah

You are my fire
The one desire
Believe when I say
I want it that way

But we are two worlds apart
Can't reach to your heart
When you say
That I want it that way

Tell me why
Ain't nothin' but a heartache
Tell me why
Ain't nothin' but a mistake
Tell me why
I never wanna hear you say
I want it that way

Am I your fire
Your one desire
Yes I know it's too late
But I want it that way

Tell me why
Ain't nothin' but a heartache
Tell me why
Ain't nothin' but a mistake
Tell me why
I never wanna hear you say
I want it that way

Now I can see that we're falling apart
From the way that it used to be, yeah
No matter the distance
I want you to know
That deep down inside of me...

You are my fire
The one desire
You are
You are, you are, you are

Don't wanna hear you say
Ain't nothin' but a heartache
Ain't nothin' but a mistake
(Don't wanna hear you say)
I never wanna hear you say
I want it that way

Tell me why
Ain't nothin' but a heartache
Tell me why
Ain't nothin but a mistake
Tell me why
I never wanna hear you say
(Don't wanna hear you say it)
I want it that way
I want it that way

‘cause I want it that way

THE ONE DESIRE= my only desire, the only thing I desire or I want.

I WANT IT THAT WAY= I want it like that (not differently). Notice the common American rule: N+T=N, so he says /wɒnɪt/instead of /wɒntɪt/

WE ARE (TWO) WORLDS APART= there’s a lot of distance between us (not physical distance)

REACH TO a place= get there, be able to go there

AIN’T= isn’t (coll.). "Ain’t nothing but a heartache"= it isn’t anything but a heartache= it’s only a heartache.

AIN’T NOTHING= "it isn’t nothing". Notice the double negative. That’s incorrect in standard English but it happens in colloquial speech and dialects. It should be "it is nothing"

HEARTACHE= "a headache" is when your head hurts, feels painful. A "heartache" is when your heart hurts (not physically, but emotionally, because of love). Notice the pronunciation of the ending –ACHE (as in "ake").

WANNA= want to (again, in AmE T is often lost after N).

TO FALL APART= to crumble, to be destroyed.

THE WAY THAT IT USED TO BE= how it was. USED TO refers to a habit or situation that was true in the past but not now any more: "I used to be a soldier" (but now I’m not).

NO MATTER X= X is not important.

I WANT YOU TO KNOW= notice this construction. The situation that I want is "you know", if you know, I’m happy. "I want you to leave" (= if you leave, I’m happy because that’s what I want).

DEEP DOWN= this is a common expression that emphasises the meaning of "down", it is "down and down" (we can’t say "very down" because that means "very depressed").

INSIDE OF ME= in BrE we would say "inside me", without OF.

I guess that song was intended to be confusing.
It was written by Max Martin and Andreas Carlsson. I remember an interview with Max Martin on the former music production site tonos.com (which doesn't exist anymore) where he talked about how important lyrics actually are, and he was like "lyrics are not so important after all. I mean, look at 'I want it that way' and try to figure that out" (figure out= understand). He did explicitly mention that song to emphasize that lyrics don't matter too much, so I guess it was somehow meant to be nothing more than gibberish, just to see how people would react. (and as we know today, it has turned out to be one of the most successful songs of all time, so obviously, Max was right...)