Worry Seed is only learnt by Bellossom by tutoring in B2W2.
As to my memory, moves like Worry Seed don't show your opponent's ability; it just says "[Pokemon] acquired Insomnia!", but that's probably changed... I haven't had anything use that move on me since Gen IV.
There are other ways of knowing a Pokemon's ability, e.g. using Skill Swap, and there are a few Pokemon that learn it in Gen VI - Sylveon, Aromatisse, Spiritzee, Carbink & Reuniclus. Reuinclus is probably best, since it can learn Thunder Wave as well.
As for Worry Seed, there are some other candidates like Bulbasaur, who learns it via level up, and can also learn a bunch of spore moves & sweet scent.