There are different levels of faith.
(1) First, clear faith refers to the joy and clarity and change in our perceptions that we experience when we hear about the qualities of the Three Jewels and the lives of the Buddha and the great teachers.
(2) Longing faith is experienced when we think about the latter and are filled with a great desire to know more about their qualities and to acquire these ourselves.
(3) Confident faith comes through practicing the Dharma, when we acquire complete confidence in the truth of the teachings and the enlightenment of the Buddha.
(4) Finally, when faith has become so much a part of ourselves that even if our lives were at risk we could never give it up, it has become irreversible faith.
— Dilgo Khyentse Rinpoche
(The Excellent Path to Enlightenment)
Yes, faith is very important. If one has faith in Buddha and believe in Buddha’s words that sentient beings can become a Buddha, one will practise hard to attain enlightenment. If one has faith in Buddha and believe in Buddha’s words that everything is due to cause and effect (karmic effect), one will be able to let go of hatred towards other sentient beings who hurt them,ie. one will realise that sentient beings who hurt others are actually very pitiful. Due to their karmic effect, they will cause harm to others without realising that it is wrong. It is lucky that we have good karma and so we can study buddhism and learn to get rid of our desires, hatred and delusion, and learn to become a good man. Others are not so lucky. They ended up hurting people and accumulating more bad karma.