The situation is dire, maybe even hopeless, and everyone is losing hope faced with certain death. The Chick or The Hero have to keep their friends and loved ones not just moving but hopeful in order to survive. So they lie. They hold their loved ones close and say "It's going to be all right", or "Help is coming." The loved one may very well know it's an empty promise, but needs and wants to believe it, because the alternative is panic or an emotional breakdown.
If the situation truly is hopeless, expect them to say "close your eyes", possibly even killing them to make sure it's a painless death. If the loved one truly has no idea of what's going on, and is on the point of death, it becomes Let Them Die Happy. Expect the hero to cradle their friend as their doom approaches.
Not related to The Promise. See also Survival Mantra. Contrast with Heroic Vow. Compare Frequently-Broken Unbreakable Vow.
In The Dark Knight, Harvey Dent promises to Rachel that she will get out of their predicament alive. She doesn't. Later on, after Dent has become Two-Face, he challenges Gordon to do the same with his son whom he's about to kill.
In the original 1954 Gojira — which was a lot more serious than its camp successors — the mother of a family trapped in the monster's path soothes her children with the promise that they would be with their father soon. No prize for guessing their father's status.
Towards the end of The Way of Shadows, when Logan and Jenine have been assaulted on their wedding night, he holds her head and whispers to her that everything will be fine, she doesn't have to be afraid, it's all right... while she is bleeding to death.
In the sixteenth-century text The Prince, author Niccolň Machiavelli explicitly states that at times it is necessary for a ruler to make empty promises for the sake of his country.
In Stephen King's Firestarter, when Charlie finds out that her mother is dead, Andy tells her that everything will be all right, though he knows "as every adult knows in his secret heart that nothing is really all right, ever."
This happened in an episode of House, where the son got sick because of radioactive scrap metal. The team was able to help him a little, but he still had cancer and no immune system with which to fight it. The father still told him everything was going to be all right, even though the son was dying and there wasn't anything the doctors could do about it. Also happens on the episode "Euphoria", between Foreman and his dad, although Foreman called him on it.
Happens a lot on Law & Order, when the police tell a witness that they can protect him or (usually) her. The amount of reassurance the police give a witness is directly proportional to the odds they'll end up getting kidnapped or killed later. Cue "I told her it would all be okay!"
Pretty much happens every other episode in 24, with Jack promising to get someone out of an impossible situation. It usually doesn't work out.
Helo from the new Battlestar Galactica loves this one, although other characters do their fair share as well.
On Mad Men, it was Don's repeated empty assurances to Betty that everything would be all right after Kennedy was assassinated that finally drove her to end their marriage once and for all.
In the series finale of Angel Illyria shapeshifts into Fred and comforts Wesley in this fashion as he dies, telling him in particular that they'll be together afterward. However, Illyria consumed Fred's soul during the resurrection process.
It's implied by Illyria's changing attitudes and uncomfortable emotions that at least a fraction of Fred's soul survived, though it may have incorporated itself with Illyria's demonic essence. However, whatever may remain of it is certainly not waiting for him in the afterlife. That's okay, Wesley isn't moving on either.
An episode of Criminal Minds had Hotch questioning the only witness to an arson, a woman who'd lost her husband and son in the same fire, and at the end reassuring her they were both waiting for her outside. He'd been specifically told by the doctor he could tell her whatever he wanted because she'd not live long enough to know any different.
In Haven Audrey will often tell someone that things will be okay as she tries to fix whatever damage the episode's Troubled person has caused. When the police chief is about to die she can't do anything to help him and says nothing. This infuriates Nathan who would have preferred that she at least gave an Empty Promise to comfort his father.
Buffy the Vampire Slayer. The "close your eyes" version happens in the Season 2 finale. Angel's soul has been restored, but Buffy can see over his shoulder the vortex that's about to pull them into the hell dimension. She kisses Angel and then runs him through with a sword, sealing the rift.
Played straight then immediately inverted in Doctor Who "Flesh and Stone"-
Amy Pond: So what's wrong with me? River Song: Nothing, you're fine. The Doctor:[Scans her status] Everything, you are dying. River Song:Doctor! The Doctor: Yes, you're right — If we lie to her she'll get all better!
This is the reason Adell holds Honor Before Reason in Disgaea 2: He became a victim of an empty promise when his parents went off to fight Overlord Zenon, promising to come back. They never did. It later turns out Zenon brainwashed them and turned them into his minions, and Adell is forced to kill them without ever learning their identities.
Played for all its tear-jerking worth in Persona 3. Aigis tearfully promises that she'll devote her life to protecting the main character while, depending on your dialogue choices, he asks her not to cry and tells her it'll be okay. In reality, he's dying in her arms, and, though not outright said, it's likely they both know it.
In You's route in Ever17, You and the Kid are discussing the Kid's apparent ability to predict the future when the Kid says they'll definitely be rescued. You asks if that's a premonition; the Kid says that it's a promise. If you get the Bad End, the Kid ends up lamenting his inability to keep his promise as they both die.
Subverted in the same game: Takeshi promises Tsugumi he won't die as he launches himself out of their submarine so it will float to the surface. He drowns. However, in the True Ending, he manages to survive thanks to Hokuto/Blick Winkel.
Robot Chicken uses it in a horrifically bleak, though still funny, Black Comedy way, as Voltron's Combining Mecha sequence is taking so long that the enemy's destroying the space station that'd called for help in the meantime. The general's young sidekick is dying in the wreckage, blind and crippled from his injuries, and asks if Voltron's arrived. The general lies and tells him yes, Voltron's here and it's all going to be okay now, before shooting him so he'll die painlessly.
In ReBoot, this trope is subverted. When Enzo appears to be losing a game against the user, Andrala promises Frisket everything will be ok, and resets their icons. When the game cube vanishes, it appears as though Andrala had made an empty promise, which is partly true; by resetting their icons to game sprite mode, she ensured the three of them would live even if they lost the game, but they wouldn't be able to return to Mainframe.