To a native speaker of English these two words sound very different and, unless they have some knowledge of different languages' sound systems, would probably be surprised that learners from some linguistic backgrounds find it difficult. To us the vowel sounds are different, made with the tongue in a different position. It is not a question of vowel length.
The reason you find it difficult is because, from a very early age, your brain became attuned to the sounds of your own language and concentrated on making the distinctions that are important in that language and stopped making distinctions that were not important. If I were to learn your language there would probably be sound differences that are obvious to you, but which I would struggle with