I don't know if you will like, but for me, one of the saddest song from here I have ever heard is from a singer called Roberto Carlos. Is a pretty old song and he sings: "I have many things to tell to you, but just with words I can't say. How great... is my love... for you
when I'm feeling in love with someone I'm used to listen. haha
"Don't forget even for a second that I have the greatest love in the world. And there's nothing to compare with it... How great is my love... for you"
The lyrics is very simple.