Read the following song lyrics and answer the question.

We Belong To gether
(By Randy Newman)

Don't you turn your back on me
Don't you walk away
Don't you tell me that I don't care
'Cause I do

Don't you tell me, I'm not the one
Don't you tell me, I ain't no fun
Just tell me you love me like I love you
You know you do

When we're together
Gray skies clear up
And I cheer up
To where I'm less depressed

It's sincerely
From the bottom of my heart
I just can't take it
When we're apart

We belong together
We belong together
Yes, we do
You 'll be mine, forever

We belong together
We belong together
You know, it's true
It's gonna stay this way, forever
Me and you

If I could really talk to you
If I could find a way
I'm not shy, there's a whole lot I wanna say
Of course, there is

Talk about fr iendship and loyalty
Talk about how much you mean to me
And I promise to always be by your side
Whenever you need me

The day I met you
Was the luckiest day of my life
And I bet you feel the same
Least I hope you do

So don't forget me
If the future should take you away
So you'll always be
Part of me

We belong together
We belong together
Wait and see
It's gonna be this way forever

We belong together
We belong together, honestly
We'll go on this way forever
Me and you
You and me

(Adopted from: https://genius.com/Randy-newman-we-belongtogether-from-toy-story-3-lyrics (April 12, 2019))

What is the message of the song?