Answer:
Step-by-step explanation:
You doubtless imagine that I have acquired all the wealth and luxury that you see me enjoy without difficulty or danger, but this is far indeed from being the case.
This first sentence answers what Sinbad thinks the person he's talking to thinks. Sinbad knows he is wrong if that's what he thinks. This sentence warns the listener not to draw false conclusions.
I have only reached this happy state after having for years suffered every possible kind of toil and danger.
And here is the central idea. Wealth and luxury are gained only be enduring toil and trouble.