It is a rather disturbing sentence isn't it?

in general when you have the structure:

conjugation of être followed by an infinitive you need to use:

conjugation of être + de + infinitive (when the infinitive isn't acting as a passive infinitive)

or

conjugation of être + à + infinitive (when the infinitive is acting as a passive infinitive)

A test that seems to work to determine if the infinitive conveys a passive meaning is as follows:

if the English translation to be + past participle of verb makes sense then the infinitive conveys a passive sense

examples

Ce dossier est à vérifier. – This file needs verifying

cette voiture est à vendre – This car is for sale

il est à souhaiter que - it is to be hoped that

toutes ces fenêtres sont à péparer - All these windows are to be repaired

Mon rêve est de devenir médecin – my dream is to become a doctor

son objectif est de renvoyer le President – Her aim is to sack the President.

The 'de' is because a lot of times you need a random 'de' or 'a' before a verb when you would think that the english 'to' would be implied by the verb itself, though I couldn't explain and don't know if there is a rule as to when you need to use 'de' vs 'a' vs no preposition at all.

I screwed up this exercise, but upon reflection, I think it's because of the "ne ... plus" construction. "Ne tuer plus" is "not to kill anymore" but the words get rearranged because it's an infinitive form that acts as... well, the object of "my desire." :P

EDIT: Wait, that didn't answer your question at all! I went astray from my original thinking. "Plus de" sort of means "more of" so that's what I think is being rearranged!

Concur, I started keeping a list of the strange duo sentences. Of course this gives one the opportunity to use some other helpful expressions from DL, like:

Have you come to kill us? This is the main entrance of their prison. He is eating his last meal. He dies in prison.

I wrote "my desire is no longer to kill" to avoid the split infinitive and it was marked wrong... any ideas?

I agree and Duo accepts this answer.

it's a pretty awkward sentence in English but I see your point

Hm that sounds like it means "my desire is for no more murder" as opposed to "my desire is to no longer kill"

I think you'd need "jamais" to be in there somewhere for that to work as a translation.

"Never" and "no longer" do not mean the same thing.

You haven't translated the 'plus'.

Infinitives cannot be in the middle of ''ne....pas/plus/jamais/etc'' construction, the middle should be a conjugated verb. Infinitives go after the ''pas/plus/jamais/rien/etc''

"Will" isn't used that way. "Un désir" is a wish or a desire. Your "will" is your determination, your power, strength of mind. (It is also a legal document stating what should be done with your assets after your death, but that's another thread - ha).

"Will" would be "volonté."

I think it's getting a bit far from the original. Not just the "for", but the "no more killing". That translation leaves the question of who is doing the killing quite unaddressed, whereas the French sentence clearly shows that it is the speaker who wishes not to kill any more. Quite different, really.

and ""Je peux rendre un soldat heureux ."

As I understand the French sentence, it's implying that the speaker has killed, and that they no longer wish to kill. An odd sentence, I know! I guess it makes sense if the speaker is a soldier...