Spock had to admit as he was dying that he was being overwhelmed with emotion: regret, sadness...
love. Yet to express that now, to tell the man on the other side of the glass the emotions he had
suppressed all these years would only cause James T. Kirk more pain.
No, the secret must die with him. His katra would remember.
So many chances, and they had all passed, slapped down by Vulcan ways. No way of knowing if Kirk
had loved him. No time to ask...
So he simply said, "I have been, and always will be, your friend..."