First of all there is nothing to be afraid of. Dental surgeries are usually minor procedures which are done giving local anesthetics, which means no pain and early recovery.
The "large black hole" on your tooth might be chronic caries
. It becomes large with time until it eats up whole of the tooth.. The prevention in early stages is always better. There might also be a infectious process involved with it at the bottom of the tooth within the bone. A sinus
tract or a thin tunnels forms between the infection (inside the bone) and the oral cavity, which drains the pus.
I recommend you to listen to your dentist
as this will give long time relief to you and a healthy mouth.
Well regarding the front chipped of tooth, it might have become non vital (dead). This happens after trauma if the pulp(living tissue) gets involved. Root canal treatment
has to be undergone to prevent future infections and problems. Root canal is usually a three sitting procedure but it can also be done in single sitting. A crown can then be placed, which will make your tooth look as new.
Dont worry, these procedures are very regular and normal. There is nothing to be afraid of.