I got super teary eyed when he's dying and Pepper said something like "it's okay, we're safe now, you can rest". She was in so much control of her own emotions, it was beautiful, and she said exactly what he needed to hear. Everyone else was so sad yet she remained strong and thought only of how he felt.
That trauma, that fear of not being able to protect everyone, really messed with Tony's head for the last twelve (?) years. He went to such extreme lengths, whether it was Ultron or the Accords, and it broke him when he failed. He took it harder than even Thor and that guy spent five years in denial, drinking away the pain and guilt.
So when Pepper told him it was okay for him to rest because they were safe, because he saved them all from Thanos, that was a beautiful moment and the perfect end to Tony Stark's story.
