The very first sign of a very good friend, not necessarily a true friend is that we are not worried about courtesies. You will call your friend at any hour and talk without any thought of time in your mind. Similarly, whenever you need support, you will call a very good friend and ask him/her to help you out. They expect the same from you. Another important trait of such relations is that we are not much worried about exposing ourselves. We speak about everything in our mind without worrying about what our friends will think. We are sure that they will take our talk in the spirit it was made. We are unguarded and open with friends in our talk.
A true friend is a little more than a very good friend. A true friend will support you even if it hurts his/her own interest. A true friend will understand your motives and needs and will be with you without any analysis or criticism. A true friend will come forward to help without any request and be with us in need without showing it or expecting anything in return. With a true friend, you can be sure that you will get help to the extent possible by him/her. Nothing will remain unturned. A mother is a true friend of her children. If we share such relations with an adult we can say that we are true friends.
A true friend makes no excuses of having work or appointments or anything but will be with you whenever you need him/her. In your hour of desperation, a true friend will support you even if the whole world opposes you. A true friend is not an opportunist. A true friend means to have someone who is like mother, as I said earlier. Instead of having hundreds of good friends, if you have a true friend, treat yourself lucky. If you can also become a true friend of someone, you will be blessed, because it is much easier for all of us to expect but very difficult to give. Be a true friend yourself first.