I don't know why, but each time it's "sanare" they want "to heal",
and each time it's "to make healthy", they want "sanus facere".
So, if you don't want to fail the exercises, just stick to this.
But I don't know if it makes really sense, as I don't really see the difference in the meaning, apart from the copycat structure in English and Latin.
Maybe "make healthy" could mean that you make everything to promote good health, and a flourishing equilibrium in someone, and healing is simply to cure someone who is sick? I don't know. But in the kind of sentence they use them, we don't really see the difference. I hope they'll improve them to show us this difference, if it does exist.
Yes, 'make healthy' might suggest taking someone off to a country retreat in order to help to restore to health. I think though that 'heal' is a bit of a faux ami since doctors don't 'heal' anyone.
I do understand that Duo is providing opportunities to learn these words and it is not always easy to find Latin phrases that translate 'convincingly' into English. ☘