「I do love you」是甚麼意思？

I do love you = 我愛你 (do 是用作強調)

文法上絕對正確。

我真的愛你

I do love you = 係! 我係愛你
通常係有人問 "do you love me?" 答 "yes, I do love you!'

文法無錯﹐意思是: "我係鍾意你"

No problem in grammar

I love you = simple/basic presentation

with the word 'do', it strengthens/emphasizes your meaning
I DO love you = of course I love you / I really love you
=longer version of "yes I do"

same theory:
I DID close the door when I left!
= I really have closed the door when I left!
= Of course I closed the door when I left!
= Yes I did!

There is no mistake.
「I do love you」is correct !!!
It means more than I love you.
It has a stronger stress and feeling.

it's correct
sometime we use verb to do to express strong feeling
same meaning as ''I love you"

ie. I did do it---same as '' I did it'' but stronger and more aggressive; or
I do want to eat!---same as I want to eat...