User blog comment:Zathronas/Speculative author, Volume 3: Jaune Arc/@comment-3257939-20141120063640/@comment-24218038-20141120145054

Here's my reasoning for the semblance.

Now remember, I said that his semblance might be different but in the same general category.

Jaune's feelings are all about extremes and he never hides them. He has a crush to Weiss? immediately tries something about it.

He gets depressed? he huddles himself in front of a door and looks like a puppy who just been scolded.

When his emotions are high, everyone knows

When his emotions are low, the same.

His semblance will be something that cover 2 extremes and will probably be offensive in nature since he has a pretty good shield already. I would also put money that it will complement Pyrrha's semblance.

Thus my choice.