Translation of indefatigable in German

We want to fly there again on Christmas, depending on Jenny's work. Maya entered kindergarden last week, and there were a lot of tears (mainly by her mother and not by herself. I guess that is natural.
We would love, if you could renew it, since we did a lot of updates to our site, such as visual lessons (lessons with images), lesson sharing, dictionary, verb conjugation tables and much more...
Your offer seems interesting to me. The language exchange is one of my future projects, so that we will contact you later when I am ready to discuss the ways and possibilities of learning together.