What are the central beliefs of Islam, and how are they reflected in the "Five Pillars"

The Five Pillars of Islam are core beliefs that shape Muslim thought, deed, and society.  A Muslim who fulfills the Five Pillars of Islam, remains in the faith of Islam, and sincerely repents of his sins, will make it to Jannah (paradise). If he performs the Five Pillars but does not remain in the faith, he will not be saved.


Shahada 
The Shahada is the Islamic proclamation that "There is no true God except Allah and Muhammad is the Messenger of Allah."
This is the confession that Allah is the one and only true God, that Allah alone is worthy of worship, that Allah alone is the sovereign lord who does what he wills with whoever he wills.
Prayer (Salat)
Prayer involves confession of sins which begins with the purification of the body and ends with the purification of the soul. Prayer is performed five times a day. The first prayer is at dawn and the last at sunset.
Fasting (Saum)
The month of Ramadan is the month of fasting in Islam. It is an act of worship where the faithful follower denies his own needs and seeks Allah. Usually, this fasting entails no drinking, eating during, or sexual relations during the daylight hours for the entire month of Ramadan.
Alms-giving or charity (Zakat)
Charity given to the poor. It benefits the poor and it helps the giver by moving him towards more holiness and submission to Allah.
Pilgrimage (Hajj)
This is the pilgrimage to Mecca. All Muslims, if they are able, are to make a pilgrimage to Mecca. It involves financial sacrifice and is an act of worship.  Muslims must make the pilgrimage the first half of the last month of the lunar year

Assalamualaikum.
If you ask me, what is the centre of islamic belief, I would say that it is tauhid.
So what is tauhid actually? Tauhid is the strong faith of god. This strong faith rebirth you into a god-fear creationtowards his mighty, a keen lover towards his merciness and a robust believer towards his existness.
Well, the syahadah itself is the main fundamental of tauhid. You believe with your heart, say with the tongue and shown with your act in the tauhidness of allah. While solat is the physical proof of your tauhid to allah, fasting and zakah is the process of cleansing your body,soul and properties in the process of reborning the faith in him. Hajj is a resemblance of the highest proof of tauhidness. Because, hajj does not only test on how many dollars you ready to used in the name of allah, but it test your patientness and faith in him. Any personal question,email me at [email protected]