Complex sentence: While there, Despereaux meets Botticelli, an evil one eared rat, who tells him that he will lead Despereaux to the Pea, however, this is only an act, to make Despereaux suffer.
Split into simpler sentences: While there, Despereaux meets Botticelli, an evil one-eared rat, who tells him that he will lead Despereaux to the Pea. However, this is only an act, to make Despereaux suffer.