• Je ne fume plus. Plus maintenant

• J’ai arreté de fumer!

To elaborate and make the question less of a translation one, here’s a fun note: French expresses a lot of different ideas of negation using the same construction. You’ve heard of

ne … pas

Well, consider pas as the "vanilla" flavour of a negative sentence. You now have a lot of different flavours you can swap in, such as:

ne … guère (hardly)

Il ne pense guère à sa femme.

ne … pas non plus (either; neither)

Elle ne pense pas à lui non plus !

There are quite a number of these:

ne … jamais (never)

ne … que (only; nothing except)

ne … pas encore (not yet)

ne … point (not at all)

ne … ni … ni (neither … nor … nor)

Some of these can also be nouns and act as the subject of the sentence:

ne … personne (nobody)

Personne ne veut des bananes vertes.

ne … rien (nothing)

Rien n’est comme il semble.

ne … aucun (none; not a single one)

Aucun des droits ne doit être franchi.

Sometimes they can even be combined:

Rien n’existe que l’homme dans l’univers.

And, finally, here’s the one you’re looking for. 🙂

ne … plus (not anymore)

Je ne veux plus trouver une façon de nier la phrase.

When you’re looking for an English phrase with the word "not", or that otherwise has a negative sense, check if there’s a replacement for "pas" that will do the job!

As a final note, be aware that "ne" will often or even usually drop out in spoken French. Thus, in such contexts you should understand "jamais", "plus", "rien" as "never", "not anymore", "nothing", etc., following verbs.

Je veux plus danser.

I don’t want to dance anymore.