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The guarantee repay is 0.18 btc in 4 months.
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Guaranteed with what? Your words? They are wortless.
Please use your brain. If a complete stranger posts on a random internet forum that if you give him $5000 he guarantee that tomorrow will return to you $10000, will you give the money to him?
The only guarantee is valid collateral. If you can't provide it, you are just waisting your time here.