end

× I waited for more than one hour and, at the end, I left without her.
√ I waited for more than one hour and, in the end, I left without her.

We use at the end (of something) to refer to the end of a physical location (at the end of the street, at the end of the road, etc.) or to the end of a period of time (at the end of the class, at the end of the week). It can also be used metaphorically: at the end of the lesson, at the end of the book, etc. At the end is normally followed by of + noun.

We use in the end as an adverb that means ‘finally’. In the end is normally followed by a comma: ‘In the end, everything was OK.’ ‘I didn’t want to buy a new phone but, in the end, I had to do it.

→ See BEGINNING