When the characters end up together.
Don't cliffhang!!! Me and all me writer friends hate it!!!! Don't be lazy!!
Some people prefer a happy ending but not all "good" endings are happy. It is generally agreed that a "good" ending to a story is one that is satisfying to the audience. An otherwise promising story can be ruined by a poor ending. Common mistakes include cheating, rushing the end and ending with an unrealistic outcome. For example, solving a complex crime as a result of one too many coincidences might be considered a cheat, wrapping up all the story's loose ends in the last five or six lines can also frustrate an audience. Unrealistic endings in which, for example, all the character's problems are resolved by an unforeseen lottery win might also dissatisfy. Most satisfying endings reflect or rely upon something which is present near the start of the story. For example, a character's gloomy mood might be linked to rainy weather and their emergence into a happier place at the end of the story might be symbolised by a sunny day.
When you grasp you readers/ listeners attention with a interesting fact or by saying something that the readers/ listeners will not forget or do not know that you are going to say. Like catching them off guard.
A cliffhanger usually is a common way of ending a story. It is also very effective and leaves the reader on their toes feeling excited about what would happen next and longing for another book to come out!