Intimacy is experienced in a state of total trust and deep love. Both are needed. When 2 lovers develop deep faith in each other, they speak the language of intimacy. It's the world's most beautiful language. Inspite of its immense beauty, it is spoken only rarely. The sparse use of intimate language has its roots in the consequential fear arising out of its usage.
Before we dissect this subject, we need to define it 1st. What is intimacy ? Intimacy is the language when 2 lovers lie naked, dispensing the clothing of their egos. They drop their egos. They are totally naked, and exposed to each other. Inspite of this nakedness, they don't feel shame. Their apparent lack of shamelessness arises because they have developed total trust of each other. In this state, they don't judge. It's a state of total bliss, the highest emotional state. The lovers are experiencing the spiritual union of non-judgemental total trust. It is a state of pure joy.
When we talk of lovers, it's not only the romantic lovers. You can be a lover of your child, or your friend, or your colleague, or anyone else. This language of intimacy gets spoken naturally to your deepest, truest lovers.
The problem arises because in our daily lives there is a constant battle between the mind and heart. The mind is rational, it does not allow trust to build quickly. The heart is blind in its purity, it trusts and gives without thought and expectation. Each experience in our life, either makes us more biased towards the mind or the heart. The mind doubts, the heart trusts. The doubts of the mind are based on every heart break that has occurred. So, sometimes when experiencing the joy of pure love with our lover, suddenly the mind makes an interference in our private meeting. The mind doubts this love. This doubt is the seed which prevents total surrender to your lover. The total trust in your lover is broken. With this disturbed trust, we need to protect our delicate heart from being taken for a ride. So, we cannot surrender, we cannot trust fully our lover. Hence, most of us often say, "I fear intimacy".