An interesting matchup, and the two characters seem about the same in terms of tiers, with Scaramouche scaling up to Jack, while Penny managed to trade blows with Pyrrha. All in all, a pretty good start. But, how would the rest of the battle go? Let's see...
To start, Scaramouche would probably be able to get the first hit in. Penny tends to be fairly naive, and probably wouldn't realize how bad it would be for Scaramouche to pull out his flute until it was too late. And, in all likelyhood, the first thing Scaramouche would do would be to summon a golem. This would give Penny a lot of trouble from the get-go, but by utilizing her Aura, I have a feeling that she would be able to finish the golem. Afterwards, she would probably go for her own attack, which is when Scaramouche would summon his sword to fight her off.
But, this is where things will likely go downhill for Scaramouche. Penny has had experience fighting much more skilled warriors than Scaramouche, and the fact that her one sword can split up into many smaller swords doesn't help him. And while he has his tuning fork dagger, which would likely negate any durability she has and take her down, she would more than likely be able to dodge it or disarm him with her swords, and come in for the finishing blow. Honestly, it would be a pretty good match, but I give it to Penny with mid-difficulty. There is a chance that Scaramouche can hit her with his dagger, which would likely stop her in her tracks right there and allow Scaramouche the chance to come in for the kill, but I really do see it being more likely that Penny will come out on top here.
Winner: Penny Polendina