When I am learning a song or ‘re-learning’ (I haven’t performed this song for a few years now) I like to go through it note by note, it takes a while but really helps the notes to stick.
I had actually remembered this song differently over time, adding dotted notes etc but as your voice develops it can actually be good to give a song some time and then pick it up again! It all depends on the individual singer.
Here is the translation from German in to English of Heimliches Lieben:
Secret Love
Oh you, when your lips touch me,
Desire would bear my soul away;
I feel a nameless trembling
Which swells my breast.
My eyes flame, a glow colors my cheeks;
My heart beats with an unknown longing;
My mind, lost in the stammering of my drunken lips
Can hardly compose itself.
In such a moment my life hangs
On your sweet lips, soft as roses,
And, in your dear embrace,
Life nearly deserts me.
Oh would that my life could escape from itself,
My soul aflame in yours!
Oh that lips burning with longing
Must part!