This is a cover by Boyce Avenue on the song of Taylor Swift 

it's only my second tab so please comment for some changes :)

capo on 3

*listen to the video for the strumming
*all chords are relative to capo

intro:
  G2
|-----|
|-12--|
|-12--|
|-x---|
|-10--|
|-x---|

verse
  G2  D  E  C
|--------------|
|-12-----------|
|-12--7--9--5--|
|-x---7--9--5--|
|-10--5--7--3--|
|--------------|

first chorus
  E  C  D  G  D
|----------------|
|----------------|
|-9--5--7--12-7--|
|-9--5--7--12-7--|
|-7--3--5--10-5--|
|----------------|

(ooh part)
  Em    C     D      G   D
|-0~----0~----2~----333-222-|
|-0~----1~----3~----333-333-|
|-0~----0~----2~----000-222-|
|-2~----2~----0~----000-000-|
|-2~----3~----0~----000-000-|
|-0~----0~----0~----333-000-|

you can replace the Em with Em7:
|-3~---|
|-3~---|
|-0~---|
|-2~---|
|-2~---|
|-0~---|

VERSE

do the ooh part for the whole second chorus and just put your own flavor to the strumming

bridge
  C     Em    C     D
|-0~----0~----0~----3~----|
|-1~----0~----1~----2~----|
|-0~----0~----0~----3~----|
|-2~----2~----2~----0~----|
|-3~----2~----3~----0~----|
|-0~----0~----0~----0~----|

Chorus (do the ooh part till the end and just put your own flavor to the strumming)

outro:
   G
|-333-|
|-333-|
|-000-|
|-000-|
|-000-|
|-333-|


Once upon time
A few mistakes ago
I was in your sights
You got me alone
You found me
You found me
You found me

I guess you didn't care
And I guess I liked that
And when I fell hard
You took a step back
Without me, without me, without me

And he's long gone
When he's next to me
And I realize the blame is on me

Cause I knew you were trouble when you walked in
So shame on me now
Flew me to places I'd never been
Till you put me down oh
I knew you were trouble when you walked in
So shame on me now
Flew me to places I'd never been
Now I'm lying on the cold hard ground
Oh, oh, trouble, trouble, trouble
Oh, oh, trouble, trouble, trouble

No apologies
He'll never see you cry
Pretend he doesn't know
That he's the reason why
You're drowning, you're drowning, you're drowning

And I heard you moved on
From whispers on the street
A new notch in your belt
Is all I'll ever be
And now I see, now I see, now I see
He was long gone
When he met me
And I realize the joke is on me

I knew you were trouble when you walked in
So shame on me now
Flew me to places I'd never been
Till you put me down oh
I knew you were trouble when you walked in
So shame on me now
Flew me to places I'd never been
Now I'm lying on the cold hard ground
Oh, oh, trouble, trouble, trouble
Oh, oh, trouble, trouble, trouble

When your sadest fear comes creeping in
That you never loved me or her or anyone or anything
Yeah

I knew you were trouble when you walked in
So shame on me now
Flew me to places I'd never been
Till you put me down oh
I knew you were trouble when you walked in
So shame on me now
Flew me to places I'd never been
Now I'm lying on the cold hard ground
Oh, oh, trouble, trouble, trouble
Oh, oh, trouble, trouble, trouble

I knew you were trouble when you walked in
Trouble, trouble, trouble
I knew you were trouble when you walked in
Trouble, trouble, trouble!