The Belief has different levels. The highest level of belief is Certitude, which the chosen ones of God and prophets would attain.
"The first is the independent investigation of truth; for blind imitation of the past will stunt the mind. But once every soul inquireth into truth, society will be freed from the darkness of continually repeating the past. " Selection From the wrtings of Abdulbaha, p255
"...by religion is meant that which is ascertained by investigation and not that which is based on mere imitation, the foundations of Divine Religions and not human imitations." Selection From the wrtings of Abdulbaha, p296
"...they that tread the path of faith, they that thirst for the wine of certitude, must cleanse themselves of all that is earthly—their ears from idle talk, their minds from vain imaginings, their hearts from worldly affections, their eyes from that which perisheth. They should put their trust in God, and, holding fast unto Him, follow in His way. Then will they be made worthy of the effulgent glories of the sun of divine knowledge and understanding, and become the recipients of a grace that is infinite and unseen, inasmuch as man can never hope to attain unto the knowledge of the All-Glorious, can never quaff from the stream of divine knowledge and wisdom, can never enter the abode of immortality, nor partake of the cup of divine nearness and favour, unless and until he ceases to regard the words and deeds of mortal men as a standard for the true understanding and recognition of God and His Prophets." Baha'u'llah - Book of Certitude
The Valley of Search
"The steed of this Valley is patience; without patience the wayfarer on this journey will reach nowhere and attain no goal. Nor should he ever be downhearted; if he strive for a hundred thousand years and yet fail to behold the beauty of the Friend, he should not falter. For those who seek the Ka‘bih of “for Us” rejoice in the tidings: “In Our ways will We guide them.” In their search, they have stoutly girded up the loins of service, and seek at every moment to journey from the plane of heedlessness into the realm of being. No bond shall hold them back, and no counsel shall deter them.
It is incumbent on these servants that they cleanse the heart—which is the wellspring of divine treasures—from every marking, and that they turn away from imitation, which is following the traces of their forefathers and sires, and shut the door of friendliness and enmity upon all the people of the earth. " The Seven Valleys of Baha'u'llah
Qur'án 29:69: “And whoso maketh efforts for Us, in Our ways will We guide them.”