Avengers: Infinity War - What Does The Ending Really Mean?
10. But At A Cost
At first, the last scene Thanos shared with young Gamora - which comes after he clicks his fingers, and looks like it's set on the Soul World - is seemingly just a visual representation for what he's had to sacrifice. She asks what it cost him to achieve his goal, to which he replies "everything."
That alone makes for a good scene in terms of the character's motivations and depth, but it's nothing we hadn't already gleaned from his terrific, emotional final scene with the adult Gamora. Since the movie is so jam-packed already, it suggests there's more to it.
That he has to see his daughter again before getting exactly what he wants indicates that at the very least she'll be there as a painful reminder of what he had to give up to realise his desire. It's this, in turn, that will make him perhaps feel a sense of regret over his actions. If anything could spur Thanos to have a change of heart, it's the one thing he loves in the universe.
That doesn't necessarily mean he'll rectify it all or go to the Soul World to save her, but this scene means those possibilities are now on the table, especially given the lengths they go to in order to make him an understandable antagonist.