Complex sentence: Season 5 also revealed that Penny was a bully during her time at school: however, she seemed to be genuinely unaware of the hurt her actions had caused, and upon her realization, she attempted to make amends with those she tormented, with little success.
Split into simpler sentences: Season 5 also revealed that Penny was a bully during her time at school. Upon her realization, she attempted to make amends with those she tormented, with little success.