There are a number of questions to consider. What type of rod (carbon blank, fiberglass), how long, what power and action, how far down the rod is the break. Generally anything you do will affect the sensitivity. Most often you best course is to cut the rod below the break and install a new tip. This prevents further cracking and can save a good rod. If you are unsure about the repair process, visit a good fishing store near you (take the rod with you) and often there is an experienced person to give you some ideas.