《I'm Sure》的歌詞如下：
I'm sure
You will come back again
To my life
When I feel alone
Every day and night
I keep thinking about you
How I miss you
How I want you back
Oh I know you might be far away
But my heart will keep on singing your song
Even if you don't hear it anymore
Because I'm sure you will come back again
You were my world, my everything
Now I'm left with nothing but memories
But I won't give up
I won't give in
I'll keep on waiting for you
Every day and night
I keep thinking about you
How I miss you
How I want you back
Oh I know you might be far away
But my heart will keep on singing your song
Even if you don't hear it anymore
Because I'm sure I will be fine
Even without you here by my side
Because I'm sure my love will stay with me forever
I'm sure my heart will always remember you.
這首歌曲表達了對於曾經的愛人的思念和對於未來的希望，即使對方已經離開，但是對愛情的執著和對未來的信念會一直陪伴著自己。