use of cousins

[aasia]

is the following sentence incorrect n if so then why
all my female cousins are not intelligent but are honest.

[asdf1234]

is the following sentence incorrect n if so then why
all my female cousins are not intelligent but are honest.

Please ask your question properly using the correct punctuation and capitalization.

[Barb_D]

Aside from the missing capitals and punctuation, what do you think is NOT correct?

[asdf1234]

There's also a clipping (n). Anyway, I think there is a missing preposition between "all" and "my cousins". I don't usually put together "all" and "my" just like that. However, if it's just "all" followed by any noun, the preposition is not used.

[Tdol]

You can say all my cousins or all of my cousins​- the preposition is optional.

[Tdol]

is the following sentence incorrect n if so then why
all my female cousins are not intelligent but are honest.

I would rewrite it and use something like:
My female cousins aren't very intelligent, but they're all honest.

[aasia]

Actually this question was asked in a class test for sentence correction as follows
Question: My all cousin sisters are not intelligent but they have honest.
I wrote : All my female cousins are not intelligent but are honest.
Teacher wrote: All my cousins are not intelligent but have honesty.
n I disagree with my teacher...m looking for sum one to guide me properly.

[bhaisahab]

Actually this question was asked in a class test for sentence correction as follows
Question: My all cousin sisters are not intelligent but they have honest.
I wrote : All my female cousins are not intelligent but are honest.
Teacher wrote: All my cousins are not intelligent but have honesty.
I disagree with my teacher. I'm looking for someone to guide me properly.

Your sentence is better than your teacher's, but it's still not natural English. Tdol gave you a good alternative in post #6.

[Grumpy]

n I disagree with my teacher...m looking for sum one to guide me properly.

You should write " I disagree with my teacher, and I am looking for someone to guide me properly."

[HanibalII]

I would rewrite it and use something like:
My female cousins aren't very intelligent, but they're all honest.

Personally, I wouldn't include 'all' because stating 'My female cousins' already specifies the amount. In that wording, it is obvious that the person is referring to all of his female cousins.