There is evidence that the Baha'i Faith is truth. But you have determine for yourself through independent investigation which involves by the way spiritual perception as well as reason. Here is what Baha'u'llah asked of us to be "true" seeker:
But, O my brother, when a true seeker determineth to take the step of search in the path leading to the knowledge of the Ancient of Days, he must, before all else, cleanse and purify his heart, which is the seat of the revelation of the inner mysteries of God, from the obscuring dust of all acquired knowledge, and the allusions of the embodiments of satanic fancy. He must purge his breast, which is the sanctuary of the abiding love of the Beloved, of every defilement, and sanctify his soul from all that pertaineth to water and clay, from all shadowy and ephemeral attachments. He must so cleanse his heart that no remnant of either love or hate may linger therein, lest that love blindly incline him to error, or that hate repel him away from the truth. Even as thou dost witness in this day how most of the people, because of such love and hate, are bereft of the immortal Face, have strayed far from the Embodiments of the divine mysteries, and, shepherdless, are roaming through the wilderness of oblivion and error. That seeker must at all times put his trust in God, must renounce the peoples of the earth, detach himself from the world of dust, and cleave unto Him Who is the Lord of Lords. He must never seek to exalt himself above anyone, must wash away from the tablet of his heart every trace of pride and vainglory, must cling unto patience and resignation, observe silence, and refrain from idle talk. For the tongue is a smoldering fire, and excess of speech a deadly poison. Material fire consumeth the body, whereas the fire of the tongue devoureth both heart and soul. The force of the former lasteth but for a time, whilst the effects of the latter endure a century.
151 he shall enjoy the blessing conferred by the words: “In Our ways shall We assuredly guide him.”
(The Kitáb-i-Íqán)
www.bahai.org/r/477357906
I should hasten to add that if this seems impossible, in my opinion He is talking about a condition of true seeking that takes a person to the highest realm of recognizing Baha'u'llah. In a general way, though, the more we meet these conditions the better our chance of finding the truth.
Know ye from what heights your Lord, the All-Glorious, is calling? Think ye that ye have recognized the Pen wherewith your Lord, the Lord of all names, commandeth you? Nay, by My life! Did ye but know it, ye would renounce the world, and would hasten with your whole hearts to the presence of the Well-Beloved. Your spirits would be so transported by His Word as to throw into commotion the Greater World—how much more this small and petty one!
(The Kitáb-i-Aqdas)
www.bahai.org/r/991129466