Trettel rhymes with:
gretal, gretel, betel, gettel, gettle, gretal, gretel, hettel, kettell, kettle, metal, mettle, nettle, petal, resettle, settle, unsettle, zettel, zettle
Trettel sounds like:
tartly, thirdly, throttle, tordella, tortilla, treadwell, treadwheel, trudel, trudell, turtle