For @Anacybele, since @Elieson has given his support for the battling Robin map, I whipped this up especially for you, which I believe you have all the required units ready and gearing already for the Navarre battle. It's 100% foolproof since I've ran it myself.
Okay, first off, just to make sure, here's the units you need (no skill inheritance needed)
Lv 40 5* Sharena
Lv 40 4* neutral Atk Palla with Atk+1 seal equipped (so she has 38 atk)
Lv 33 4* Olivia (at least the one I used)
Lv 1 2* F Robin
So, let's start. Turn 1
Turn 2
Turn 3
Let's see what Turn 4 looks like shall we
Turn 5
It all ends in this turn
I hope you beat it with this, Ana. You should be able to do it if you follow this exactly. Wings are fun.