Friendship is not simply a "relationship", knowing someone, conversing with that person, or dealing with that person in business, school, or in casual acquaintance. True friendship is not just a "relationship", but self-sacrificing love. A friend is also one who supports, sympathizes, and is a person in whom you can confide. There are unique qualities that a person must have to be considered a friend.
An acquaintance is not automatically considered a friend. Just because you know someone does not mean there is an instant friendship.This does not mean that an acquaintance cannot change into a valued friendship. There are qualities that a friend must have, but time is also a factor. A friendship can develop in as short as a day, or it could take as long as a few years for full development.In the end, if time is taken for full development, then a real friendship will develop.The main way that trust is built up is with time. When you and a friend have trust, there will usually be a strong friendship.