How to speak English in a pure pronunciation?

Unless you have a method of being reborn to native English parents and acquiring their phonetic targets during your subsequent childhood, there is no solution.

BTW There is no such thing as "pure pronunciation"...only the situation of detection of "a foreign accent".

Of course, as a native of the city of New York, my pronunciation is the pure pronunciation. We don't hand it out, though, like fliers on the street corner.

Thanks for your suggestions .I will adjust the way I learn English !

Maybe you could listen to British English and repeat after it.Watching more movies and making friends with foreigners are also good ways for your prounciation.In a word,prounciation is something we have to keep on everyday.The most important is that you should keep on going. Fighting!