How can a Muslim attain the pleasure of Allah Almighty and become a sincere believer, and does this require memorizing the the Qur'an and Hadith?

Memorizing the Qur’an and Hadith is not a condition for Allah Almighty to be pleased with a servant, nor is it an individual obligation upon every person. Rather, it is a communal obligation (fard kifayah) that, if fulfilled by some, absolves the rest from its incumbency. This is to ensure the availability of what is indispensable for people in establishing their religion.