Shalom, I have read in a publication of an Orthodox rabbi here in my country, that even if I am not "Halachically" Jewish (because my Grandfather was Jewish/Sephardic, but my Grandmother was not-jewish, and therefore my mother is not jewish), the conversion process in my case, in order to become a Jew, is much easier because I have a Jewish ancestry... Is that true? Thank You

Not really; there is the notion of "Zerah Yisrael" if the father is Jewish, but in practice it should not make any difference especially since your case is different. In any event you should speak to the Beth Din for the procedure.