Complex sentence: Thumbelina sneaks out of Miss Fieldmouse's home to visit Jacquimo, reflecting that marrying Mr. Mole might be her best available option, but Jacquimo then wakes up, and Thumbelina removes the thorn from his wing.
Split into simpler sentences: Thumbelina sneaks out of Miss Fieldmouse's home to visit Jacquimo. He wakes, and Thumbelina removes the thorn from his wing.