This is RE your original response to oryx, about the issue of winning Harry's trust.
When was Severus supposed to have had the moment to win Harry's trust, and failed or chose not to try? You seem to be speaking about winning Harry's trust RE passing on the Harrycrux info in DH specifically - something Severus had absolutely no idea about half a dozen years beforehand when he first met Harry and they established their mutually hostile relationship. So obviously winning his trust with an eye towards eventually passing on the message to commit assisted suicide was not on the agenda then, or at any time before 6th year. (Winning his trust independently of this goal is another matter, but I won't repeat oryx's and others arguments about that here.)
During 6th year, Dumbles instructed Severus not to tell Harry about the Harrycrux until the last moment, so melting the ice between them and passing on the message during 6th year was out of the question. Suddenly pursuing a friendly relationship with Harry during that year *without* the intention to pass on the message right away would have rung alarm bells in everyone's minds on both sides, given their relationship over the previous five years. It also would quite likely have backfired and caused Harry to *distrust* Snape even more after the Tower affair: he'd see it as a deliberate betrayal of himself personally, and would make him more resistant to listening to Severus later.
He also couldn't tell Harry anything too soon (including telling him about Dumbles' plan to have Snape kill him ahead of time) because of Voldie's scar-o-vision. This includes trying to explain things during the silver doe scene, since it's not yet time for Harry to die and Snape doesn't know ahead of time when that will occur - he has only a certain cue to look for, one totally independent of anything he can control. And the greater the time ahead of Harry's scheduled demise that Snape tells him anything, the greater the chance Voldie will peek into his head and perhaps discover Snape's role. (He also has to remain at the school and attempt to subtly rein in the Carrows/appear to Voldie to be doing his job, so trailing around after Harry waiting for the right moment is not an option.)
After the Tower affair, the scene in the Shack is the first time Snape and Harry come face to face since Dumbles' death, it doesn't occur on Snape's terms although he attempts beforehand to find Harry himself, and when Harry shows up Snape has minutes to live.
When exactly was he supposed to win his trust in order to make sure the message would be believed?
When was Severus supposed to have had the moment to win Harry's trust, and failed or chose not to try? You seem to be speaking about winning Harry's trust RE passing on the Harrycrux info in DH specifically - something Severus had absolutely no idea about half a dozen years beforehand when he first met Harry and they established their mutually hostile relationship. So obviously winning his trust with an eye towards eventually passing on the message to commit assisted suicide was not on the agenda then, or at any time before 6th year. (Winning his trust independently of this goal is another matter, but I won't repeat oryx's and others arguments about that here.)
During 6th year, Dumbles instructed Severus not to tell Harry about the Harrycrux until the last moment, so melting the ice between them and passing on the message during 6th year was out of the question. Suddenly pursuing a friendly relationship with Harry during that year *without* the intention to pass on the message right away would have rung alarm bells in everyone's minds on both sides, given their relationship over the previous five years. It also would quite likely have backfired and caused Harry to *distrust* Snape even more after the Tower affair: he'd see it as a deliberate betrayal of himself personally, and would make him more resistant to listening to Severus later.
He also couldn't tell Harry anything too soon (including telling him about Dumbles' plan to have Snape kill him ahead of time) because of Voldie's scar-o-vision. This includes trying to explain things during the silver doe scene, since it's not yet time for Harry to die and Snape doesn't know ahead of time when that will occur - he has only a certain cue to look for, one totally independent of anything he can control. And the greater the time ahead of Harry's scheduled demise that Snape tells him anything, the greater the chance Voldie will peek into his head and perhaps discover Snape's role. (He also has to remain at the school and attempt to subtly rein in the Carrows/appear to Voldie to be doing his job, so trailing around after Harry waiting for the right moment is not an option.)
After the Tower affair, the scene in the Shack is the first time Snape and Harry come face to face since Dumbles' death, it doesn't occur on Snape's terms although he attempts beforehand to find Harry himself, and when Harry shows up Snape has minutes to live.
When exactly was he supposed to win his trust in order to make sure the message would be believed?