As the others have explained, we usually use “won’t” in conversation. The difference in sound between “won’t” and “want” is significant, so you can certainly learn it. If I were to attempt to spell the American pronunciation using something like Spanish orthography, it would be something like “uount” for “won’t” and “uant” for “want”. How could we possibly confuse OU and A? Now in RP (so-called standard British pronunciation), the vowel in “want” is a bit rounded and a tiny bit backed, so that it might sound a tiny little bit like a Spanish O to you, but it’s not a real O by any means. Also the O in “won’t” will still be a diphthong as in American English (but more or less fronted than in American English) — again, the sounds are totally different. (RP has a 4-way distinction between the broad-A of “barn”, the rounded A of “Bonn”, the open O of “born”, and the closed O (actually a diphthong) of “bone”. Luckily, you don't have to worry about that. In American, the vowel in “Bonn” is the same as in “barn”, so the difference is the R sound. (Note: Some US east-coast accents have the 4-way distinction as in RP, but this is not really necessary for American English. And speakers of General American and RP can easily understand each other. It seems to me that if you go and get more listening practice, your listening skills will skyrocket quickly. If you tell us what you’re currently doing for listening practice, we may be able to makes some suggestions.

"Won't" is the usual spoken form. To a native speaker, "won't" and "want" are clearly different. It can be difficult for Spanish speakers to distinguish English sounds unless they have had listening lessons or considerable exposure to spoken English. Most dialects of English have about 45 meaningful sounds (phonemes) whereas most dialects of Spanish have about 32. For example, North American English has three vowels, /æ/ as in bat, /ʌ/ as in but, and /ɑ/ as in bot, which are close to the Spanish /a/ in bala. Some Spanish speakers don't hear the difference between bat, but, and bot and some Spanish speakers hear the difference but pronounce these words identically using the Spanish /a/. In contrast, French has about 45 meaningful sounds (not all the same as English), so French speakers have fewer new sounds to master.

Hi, Andres! "Will not" and "won't" are synonyms, so there is nothing wrong with using "will not" in place of "won't." However, as Peter already mentioned, native speakers use "won't" a lot (more often than "will not" because it's shorter), so you will have to train your ears to hear the difference between "won't" and "want."

“An editor won’t accept an article with that bland headline.” — something I heard, repeatedly, in the last hour.

Thank you Doug. The "aah" in "want" would be an American Pronounciation