Anyone else notice that Catherine's confession in the car about her great lost love is strikingly similar, in fact almost identical to Greta's final confession to Gabriel of her lost, dead poet love from THE DEAD? Too close to be coincidental, I think. But at least Rossellini borrows from excellent sources.
I grant you some similarities, but there are differences.
In “The Dead”, Greta’s confession purges her of the pent-up emotion and she falls asleep. Her words have excited pity in Gabriel, whose meditation expands from the one dead man to all the dead.
In “Viaggio in Italia”, Katherine’s confession does not bring her peace because she still has too many unresolved areas in her life. And Alex seems to remain insensitive and uncaring in general, though capable of slight tenderness to the prostitute and to Maria.
After the uncovering of the dead couple in Pompeii, where Katherine sees their long-terminated lives as a symbol of her unfulfilled existence, the transformation comes while the two are caught up in the religious procession. Though the determinedly secular James Joyce might call it no more than an epiphany, one could see it as a miracle.