Consider the action movie: our hero battles the villain(s) for an hour and fifty minutes, but in the end? We know he'll win. That bullet he just took to the shoulder? Nah. Not gonna kill him. That train speeding his way as he chases the bad guy? Not gonna kill him. We know that in the end, he'll survive and the bad guy will be violently killed by him. Predictable.
Consider the romantic comedy: two people meet, likely hate each other, but Fate continues to place them in each other's paths. (There's also usually the sidekick guy and the sidekick girl, who put the "comedy" in romantic comedy). After a long series of misunderstandings and obstacles, the air is finally cleared, and our couple will look dreamily into each other's eyes and kiss while the music swells. Totally predictable.
Some people hate that kind of predictability and will avoid it at all cost. But some of us actually like it. There's an odd sort of comfort in predictability, I think. Since we know the ending, we can sit back, relax, and watch the journey. In fact, for me, the mark of a good romantic comedy is the journey---when it's unique or quirky or well-told. Or when the couple has amazing chemistry. Sure, I know they'll get together in the end. But how will it happen? That's what I'm interested in. What will their journey be?
My most favorite examples are While You Were Sleeping (quirky, original, even silly "journey" to the predictable ending), When Harry Met Sally (smart, witty dialogue and great jazz music), and Return to Me (again, quirky/original plot and sweet chemistry between the leads). I knew the outcomes of these movies the first time I saw them, but that didn't stop me from enjoying them. Over and over again, in fact. It's all about the journey.
So, when I write my women's fiction and am occasionally told the ending feels a little "predictable," I don't always see that as a bad thing. Because, hopefully, I've given the reader an interesting journey along the way, with strong characters and good chemistry between the protagonists. Some might like that kind of predictability, and some might not. And that's okay with me.