I could see parts from all 4 of these songs fitting Delena!

I Won't Give Up:

Well, I won't give up on us
Even if the skies get rough
I'm giving you all my love
I'm still looking up

And when you're needing your space
To do some navigating
I'll be here patiently waiting
To see what you find

'Cause even the stars they burn
Some even fall to the earth
We've got a lot to learn
God knows we're worth it
No, I won't give up

Everything:

And you play it coy but it's kinda cute.
Ah, when you smile at me you know exactly what you do.
Baby don't pretend that you don't know it's true.
'cause you can see it when I look at you.

And in this crazy life, and through these crazy times
It's you, it's you, you make me sing.
You're every line, you're every word, you're everything.
///
And I can't believe, uh that I'm your man,
And I get to kiss you baby just because I can.
Whatever comes our way, ah we'll see it through,
And you know that's what our love can do.

I Will Always Love You: *I see this from Damon's pov at the end of S3 & beginning of S4.

If I should stay
I would only be in your way
So I'll go but I know
I'll think of you every step of the way
///
Bittersweet memories
That is all I'm taking with me
So good-bye
Please don't cry
We both know I'm not what you, you need

And I...
Will always love you
I...
Will always love you
You, ooh
///
I hope life treats you kind
And I hope you have all you've dreamed of
And I wish you joy and happiness
But above all this I wish you love

Marry Me:

Forever can never be long enough for me
To feel like I've had long enough with you
Forget the world now, we won't let them see
///
Together can never be close enough for me
To feel like I am close enough to you
You wear white and I'll wear out the words "I love you"
And you're beautiful

Now that the wait is over
And love has finally shown her my way

"you never give up... good."