Jacques’s job came with a certain security, but it was no sinecure. He worked at a branch office (“succursale,” en français) of an underwriter, and they were a bit oversubscribed. Although he was by nature carefree, at this particular moment he was overrun, and he called me up. “Au secours!” he said. “Can you run over?”
“I’m not so sure,” I replied. “What can I give you?”
Jacques shrugged audibly. “Succour?”
“How about a sucker, au sucre?” I said.
“Sure,” he replied. I grabbed a lollipop and my jacket and headed over.
Not that a sucker is necessarily appropriate succour; although some of us may think of succour as encouragement, it really means ‘relief’ or ‘help’ – if you run to give someone succour, a bit of alimentary energy is the bare minimum, and they might prefer lawyers, guns, and money.
And in a plurality, if possible. Succour is a fake singular – the original form English took from Norman French was socours, which was subsequently mistaken for a plural. But in fact it came from Old French secours (which became modern French secours, as in au secours, ‘help!’), which was from Medieval Latin succursus, a participle of succurrere, ‘run to help’, from sub ‘under’ and currere ‘run’ – so if you are overrun, you need someone to underrun. The sense of assisting also gave rise to the French derived form succursale, ‘branch office’ (there is an English word succursal, referring to a religious subsidiary or a ‘chapel of ease’, but I’ve never seen it actually used in the wild).
Secure may seem to be related, but don’t be so sure. In fact it comes from securus, from se- ‘without’ and curus ‘care’ – compare the nearly identical sinecure, from sine ‘without’ and curus ‘care’. Securus passed into Old French and became seür, which became modern French sur(e) and English sure. And of course English also borrowed the Latin more directly to make secure.
And sucker, and sucre? Sorry. The latter is from Sanskrit (via Arabic); the former is as English and Germanic in origin as any word can be (though it does connect at the Proto-Indo-European with Latin sugo, source of French sucer ‘suck’). So it goes. Etymology solely by sound is insecure and gives no succour – it’s for suckers.
Sesquiotica 
“Safe” in Czech is also without a care: bez + péče = bezpéčný. But my favorite is “dangerous,” which becomes “not without a care” — nebezpéčný. It’s fascinating to me how the Slavic languages are constructed in the same way as other Indo-European languages, but as you say, you can’t tell that from just the sound of it.