How did Salieri feel about Mozart towards the end?
I've watched this movie many times, but this is still vague for me. Salieri's hatred first develops when he meets Mozart, who despite being childish and immature, can out-compose him with his eyes closed, despite the former's dedication to music and even voluntary celibacy. It further intensifies when he finds out Mozart slept with his dream girl and pupil.
Near the end, Salieri rescues a collapsing Mozart at the vaudeville and takes him back to his house, presumably because he can't let him die before completing "Salieri's" requiem. Salieri then lies to Mozart and tells him that the 100 ducats from the vaudeville proceedings are for the requiem, and that if he finishes tonight he's promised 100 more. Obviously Salieri isn't concerned about the abysmally sick state Mozart is in, or about eventually being caught as a liar (that lie would come out in a few days at most, when Mozart/Stanzi asks for their earnings from the vaudeville). It almost seems Salieri is going to murder him that very night, while his wife and child are gone and the requiem is finished.
Salieri begins to help Mozart finish his requiem. His obvious excitement could either be due to the pleasure of participating in composing this great music, or the thought that he gets to take credit for this after he kills Mozart. Mozart then apologizes to Salieri, a vague "general" apology to be sure, but apparently because he thought Salieri did not care for his music.
At this point, I wonder if Salieri is really going to kill Mozart. The energy between them has changed during the "composition" scene, indeed it seems that they could almost be on the brink of starting a friendship. Salieri hates God first and foremost, but his hatred of Mozart seems to evaporate here. I could be wrong, and perhaps Salieri would strangle the life out of him as soon as the last measure was written, but I can't think so with certainty.
At the very ending (the beginning of the movie) Salieri is begging for Mozart's forgiveness. Was this sincere? Did he recognize the error of his ways much later, as an old man, or did his feelings towards Mozart soften much before then?