I think there still huge different between them. as a chinese, I feel it more conforatble and more cozy to speak out the second sentence compared wtih the first one. maybe it is matter of phonetics rather than syntax. I will unintentionally speak out the "的" at the end of the second sentence even in a very light tune. the function of "的" at the end of sentence in syntax is to stress the affirmation. hoping this help

i think the first sentence is correct,too. 的in the second sentence is more like a modal words. adding 的 makes the sentence more friendly and fluent. the first one give me the feeling like stiff? but i don't think it's wrong.

Actually, both are correct. But different tones. First one sounds serious. Second one sound gentle and amenable. Second one translated into English should be like this below: If you need me help your English, I will help you, la. So bizarre Are sure you a female? Do you know Japanese female and male speak different tone? Male speaks stronger phrases and female speaks gentle phrases. If you make your Chinese tone more like a female flatter to a male is an informal conversational tone. Perhaps you need a conjunction as "if"(如果) 如果你需要我幫你的英語，我會幫你的。 Or I suppose your attitude is closer to China not Taiwan, because Taiwanese like conjunction more.

in my opinion, both of them are both good. and i feel the second one is more sincerely from the tone.

I am agree with Lily. The first and second sentences both are right, only the second with"的”in the end is to express"Certainty" more.