When you say "elle a voulu louer une couchette", it involves one precise moment whereas "elle voulait louer une couchette" means that at some point, (maybe every night, maybe she was just thinkin about it and didn't do it).
I don't know if the difference is clear:
elle a voulu : it was a precise action, something done
elle voulait: maybe she did it, maybe she didn't , maybe it was all the time: she didn't have anywhere to sleep and she wanted to hire a bed...
Thank you both. Yes i understand what you have both said, but i'm going to give a little more context.
I've taken elle voulait louer une couchette.from a text book in which a husband, who works in a railway ticket office, is telling his wife of his difficult day.
He states 'Elle voulait louer une couchette' (referring to a passenger booking an overnight train journey) But he wouldn't be saying ' She used to want to hire a bed', would he?
I'm sorry. I'm probably being a bit slow here.
Ok. More context is always usefull. Now the husband narrates his day. It's the tense that would be chosen in a book for a description: "elle se levait à 8h. elle prenait son petit-déjeuner. elle faisait la vaisselle puis elle partait au travail."
The imperfect there is the tense used to tell a story.