Let me see if I can work it out by typing it. I tend to get things as I explain them to myself.
So, Namine finds Ven's memories while putting Sora's back in the correct order. She finds all the people who are hurting and realizes they need to be saved. However, she can't tell Sora this, cause he's asleep and even once he's awake, he won't remember her or have any idea what she's talking about. So, she uses Jiminy's Journal and puts data of herself with said knowledge into the "Their hurting will be mended..." entry.
She does this with the hope that one day, they will discover the message, realize that Jiminy didn't write it, and go into the data world, where they will then repair the damage to the Journal that Namine caused during the events of CoM. And once the journal is complete, they get to the end and find Namine's message and then she tells them that said memories of pain she found are inside of the real Sora's heart and that he has to awaken said memories in order to save them. However, if he does this without preparation, it could essentially kill him, due to the pain.
And that's where I get stuck. Data Sora learned how to deal with "hurt", not the real Sora. So, how is real Sora going to call those memories to the surface if Data Sora is the one who learned how to handle those memories? I mean, I get that the point of Re:coded was to restore the Journal, which they did, so it wasn't all in vain. But still. That message was intended so that Sora would learn how to handle hurt and save all those people. But Data Sora learned it, not real Sora. So, how exactly does that work?