If you truly believe in your concept and ability to execute it, $15,000 is a small price to pay for retaining 100% ownership... you don't believe that you would be able to make that amount + interest within the term of the loan? Even with Vietnam's high interest rates (which I think are around 12% now, right?) that's still only $1,800 per year for the credit.
I know things are different there economically than here in the states, but the business process is the same world-wide... if you aren't confident you can make enough to cover the cost of the loan, then you also wouldn't be able to make enough to cover your partner's investment. And if he's the only one putting in the money, he should be the majority owner - which would make it easy for him to cut you out of the picture later if the business is only making enough to support one of you. I know that no one ever thinks their friends will do this to them, but I've seen it happen when things go south.
"The secret to discipline is remembering what you want" -- David Campbell
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