There's only one verse in this tune at the beginning, which is solely accompanied by the piano. The chords of the verse are very basic, mainly I-IV-V:
But the frequent usage of chord-inversions hides the relatively simple structure of the verse progression and creates a smooth tension.
The chorus dramatically starts with the relative minor chord (Cm) and ends with the more peaceful major tonic (Eb):
The following Interlude establishes the first key change to a joyful F major:
The chorus starts again with the relative minor chord (now in F major being Dm) creating again a bit of sweet tearfulness, which is finally enhanced by a rise in key of a whole step to Gb during the last chorus. Sentimentality at it's maximum. ;-)
Thanks to Markus for the donation and this sentimental moment.