Regarding asking for writing about some courses in my CV in which I got bad grades due to my non interest in those courses I am a masters student in an Asian country and I am looking for applying for PHD Position in Europe in pure mathematics. 

During my masters in my Institute I had a lot of applied maths courses and in some ( almost half) of applied maths courses I got 6 or 7 grade ( out of 10) despite the fact that I tried to study. But In pure mathematics courses I have very good grades and also the branch I wanted to do phd is not offered in my university. I studied it myself and did one internship and I am confident in that particular branch and I am really interested in it. ( so, studying a different topic also took considerable time from applied courses. ) 

My question is -- how to write this effectively in Cv and Whether it's right to right as I am not trying to give an excuse so that my chances of admission are not hampered. 
Please guide .
My general advice in such situations is to stress the positive in any application. Show the reviewer that you are a good candidate for success both in background and in work habits. Don't focus on explaining things that aren't positive but be prepared to respond when/if asked about them. 

While the competition for a slot in a good university is very strong, nobody is perfect. And you won't know how competitive you are until you apply. 

If you have a fairly narrow focus you intend to follow in graduate studies, focus on that and how you are especially well prepared to work in that field. Be enthusiastic, not apologetic. 



Caveat. I don't know how your grades are interpreted by your own university, not how they will be seen when you apply. But focus on the good stuff, not the bad.