Why won't I be successful in making a 230V SMPS?
Because you can't run without learning to walk first.
In this same forum, I have advised beginners over and over: You want to learn about SMPS?
Good! Start with a low voltage, low power one.
Line powered SMPS circuits are unforgiving. If you make a mistake, and rest assured that as a novice you will make plenty, and you could damage your test equipment, shock yourself, and start a small fire.
And you have to read, read, read. Read datasheets, read appnotes, read good SMPS books.
If after building a small SMPS you still want to go further, my advice is to purchase an Evaluation Kit available from many suppliers. Its advantage is that it is already a fully functional circuit which is well documented and explained, has a wide layout and plenty of test point for easy probing, and usually has options to modify or customize it.
It may cost around $50 US, but as I also have repeatedly stated, education is never free.
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Check for instance, the following Reference Design from OnSemi:
http://www.onsemi.com/PowerSolutions/evalBoard.do?id=NCP1012GEVB