Listen for these three phrases サトシ says the day before he becomes a pokemon trainer:
フシギダネ、きみにきめた!
ゼニガメ、きみにきめた!
ヒトカゲ、きみにきめた!
きみにきめた means "I choose you". きめた (chose) is actually a past tense verb, meaning the action has already been done. The present tense for きめた is きめる (choose). So even though in the English version of Pokemon, サトシ says "I choose you", in the Japanese version, it would actually be, "I chose you".
きめる is a る verb. There are two types of regular verbs: る and う. There are also the irregular verbs: する (to do) and くる (to come).
Any verb at does not end with る is an う verb. る verbs are more complicated. If the verb ends with る and the second to last syllable has an "i" or "e" sound, then it is most likely a る verb. If the verb ends with る and the second to last syllable has an "a" "u" or "o" sound, then it is an う verb.
Example う verbs: いく (iku, or to go), はなす (hanasu, or to speak), わかる (wakaru, or to understand)
Example る verbs: きめる (kimeru, or to choose), たべる (taberu, or to eat), みる (miru, or to see)
*Learn more about る and う verbs in Tae Kim's grammar guide.