Both words end in /s/, but the vowels in the final syllables are completely different. The IPA is: /əˈsɛs/ versus /ais/ (or /ʌis/). Mandarin doesn’t really have the open-E (IPA /ɛ/) as a phoneme, although you’ll hear it as the main vowel in Hanyu pinyin yan and ye (eg 言, 也). Mandarin speakers are often confused by the final consonants of English, which tend to distract them from the vowels. If you make learning English pronunciation a priority right now, learning the language will be a lot easier, more effective, and more fun. Learning the sounds of a foreign language is hard, so you need ear-training, and it would also be a good idea to read up on English phonology, or work with an expert pronunciation teacher to get started on the right foot (it’s easier to do things right the first time, instead of having to go back, unlearn, and re-learn everything). 您还有问题的话，可以让我知道。

Hello Qing, Which sound are you referring to? Do you want to know about the vowel sound 'e' in the last syllable of assess or do you want to know about the 'ss' sound? If you look in most online dictionaries, they offer an audio recording that will allow you to play the pronunciation of each word. Then you can compare the pronunciations of the words 'assess' and 'ice'. If you were taught English in school using the IPA (the International Phonetic Alphabet), then you will see how the word 'assess' should be pronounced. Otherwise, we could record the pronunciation for you if you let us know.

Thanks for all of you. I was confused by "ess" and "ice." I listened to the online dictionary but still can't distinguish them.

The other answer is perfect. I want to add to it. The schwa sound is very common. It is very quiet and changes the pronunciation of a word. Using the dictionary will help you. It has the IPA format of that word. Also, some syllables are louder and quieter than others sometimes.

/əˈses/= assess aɪs = ice They are different sounds altogether. The phonemic chart will help you. Shout out if you need help here.