The Visual Thesaurus WOTD email says:
demonstrateI say, really? People rhyme them? Not me.
This common verb, meaning "show clearly," has only a single rhyme in English, remonstrate, to which it is related etymologically though not much semantically.
The dictionary bears us both out - the words can rhyme, but only if you use one of the sometimes pronunciations. Huh. Learn something new every day...