devoir... and avoir besoin de ...

Question

I am struggling a bit with the use of these, for example "You need a new bike" I would have thought either correct but the quiz says only besoin de is correct. Have tried reading other threads but none the wiser.

Accepted Answer

In a nutshell, avoir besoin is about needing (or needing to do) something while devoir is about having to do something.
avoir besoin de qqc -- to need somethingavoir besoin de faire qqc -- to need to do somethingdevoir faire qqc. -- to have to do somethingJe dois aller au banque. -- I have to (=must) go to the bank.J'ai besoin d'aller au banque. -- I need to go to the bank.

Answer

The question related to the usage of ‘devoir’ and ‘avoir besoin de’, not avoir envie de. Chris’s answer marked correct, is not wrong, but not the answer to this question.

‘Devoir-infinitive’ (eg faire) is ‘have to (do)’ - relates to obligation, and in conditional present tense, should (do). It does not mean ‘have need of, or wanting’ something. ‘To have need of something’ is ‘avoir besoin de qqc’. Unlike ‘devoir’, ‘avoir besoin de’ can be followed by infinitive or noun, and mean ‘need (to do)’ or ‘need (something)’.

‘Devoir-noun’ changes the meaning of devoir, and means ‘to owe (noun)’. Explained in attached lesson:

Devoir vs Avoir besoin de to express "to need to" in French

Answer

Hi Maarten, thanks for pointing this out. Must have been on autopilot. I adapted my response accordingly.