Question

A Red, Red Rose

O my Luve's like a red, red rose,
That's newly sprung in June:
O my Luve's like the melodie,
That's sweetly play'd in tune.

As fair art thou, my bonie lass,
So deep in luve am I;
And I will luve thee still, my dear,
Till a' the seas gang dry.

Till a' the seas gang dry, my dear,
And the rocks melt wi' the sun;
And I will luve thee still, my dear,
While the sands o' life shall run.

And fare-thee-weel, my only Luve!
And fare-thee-weel, a while!
And I will come again, my Luve,
Tho' 'twere ten thousand mile!

What is the theme of Burns's poem?