ZuMako8: Is the reflexive pronoun you refer to the "Mi" at the start? Meaning with it present the "sentire" is to feel and without the "Mi" it could mean to hear? (I've been caught out a number od times on this question where I keep thinking it means to hear, so to understand properly would be really helpful, thanks)
A reflexive verb is one for which the object and the subject are one and the same person. So, e.g., in English you can say 'I asked him/her/you if we're going..' in which subject and object refer to different people or "I ask myself if we're going.." in which case you're using a reflexive construction: subject and object are one and the same person. As I pointed out above, reflexive constructions in different languages don't always translate the same way. That's true of the verb to "feel". In English you wouldn't use it reflexively, you'd just say "I feel better". But in Italian and German the verbs require a reflexive pronoun that properly refers back to the subject. So "Mi sento meglio" or in German: Ich fühle mich besser, where both "mi" in Italian and "mich" in German may literally mean "myself" but as I've said you wouldn't translate that idea of self in English. Let me add it's not the verb to "want" that determines the need for "mi" but the verb "sentire" or more precisely "sentirsi".
To add to what @Germanlehrerslsu so kindly contributed, think of it this way. English does not make a distinction between feeling the outer world and feeling the inner self/well-being. So, out of context, "I feel..." could mean how one feels emotionally/healthfully or what they are touching/sensing ("I feel the fresh dew on the flower."). Now, what about the sentence, "I feel well?" What does this mean? Does it mean that one is healthy or does it mean that one has a top-notch that can feel and detect anything that touches their skin and hair cells? Although it typically means the former, the sentence could potentially have both meanings. In Italian, German, Portuguese, and Spanish (and most likely French, too), the reflexive would distinguish the two meanings, with the included reflexive being reserved for the meaning of healthiness.
Sunshinejda: Here's another way to look at reflexive constructions that's not too grammatical. Think of how we use the word 'reflection' in everyday life: We see a reflection when we look into a mirror for example and who do we see? We see ourselves; if she looks in the mirror she sees herself; he sees himself; they see themselves; you see yourself -- these are all reflexive constructions in english. Now if she looks through a window and sees another female you'd say "she sees her" or "he sees him (another male) and so forth. These object pronouns (her, him) would not be reflexive since they refer to a different person than the subject - they'd be regular personal pronouns, not reflexive pronouns. Other examples: She hurt her/him (non-reflexive) vs she hurt herself (reflexive). Or: I bought him/her/them a new car (non-reflexive) vs I bought myself a new car (reflexive) In this last example, in folksy, slangy English you might even hear "I bought ME a new car" which really conveys the idea of how the reflexive pronouns work. Now not to comlicate things but to show how interesting language can be (and maybe how difficult or frustrating for non-native speakers to understand exactly how to use certain verbs) in English some verbs may be used reflexively or not, without much if any change in meaning, depending on region, education, whatever. Consider: "You've got to behave!" vs "You've got to behave yourself." One's non-reflexive, the other reflexive - now try explaining THAT to someone trying to learn English. Ok, let me excuse myself for the long-winded comment, but upon reflection I just couldn't control myself! :-)
This is a wonderful explaination for english speaking people. Until you try to learn another language you don't understand the massive amount of variation even in the simplest of sentences. I try and try but now my goals are much more realistic. Explanations such as yours at least make it easy to understand why and help to improve people's skills over the longer term. Thank you!
Just wanted to say a HUGE THANK YOU to everyone's helpful comments. So refreshing to get some help that cuts through the grammatical jargon! If you're new to this thread: read all of it before commenting as you may get your answer. Also, the whole hear or feel thing... "mi" at start turns sentire into feel, whereas "io" at start makes it hear, and the "io" can be ommitted. So, "voglio sentire meglio" is "i want to hear better" where as "mi voglio sentire meglio" is "i want to feel better". Like I said; worth reading all comments as they expain far better...