After some thoughtlessness on his part when it came to her King, and unknown to him her father, Radames had his servant, Mereb to deliver a letter of apology to Aida, where he bemoaned the complications of their relationship, yet affirming that he does love her.
Radames: I'm sorry for everything I've said
And for anything I forgot to say, too
When things get so complicated
I stumble, at best, muddle through
I wish that our lives could be simple
I don't want the world, only you
Oh, I wish I could tell you this face to face
But there's never the time, never the place
So this letter will have to do
I love you...