There isn't actually a word in the English language that is spelled "rheadine". It is possible that you may have meant "rheumatoid" or "redemption", perhaps? Either way, IPA (International Phonetic Alphabet) can be useful when it comes to understanding pronunciation. For "rheumatoid", the IPA is [ruːˈmætɔɪd]. For "redemption", the IPA is [rɪˈdɛmpʃən]. Knowing IPA can help with pronunciation if you are unfamiliar with a word.