What field will you invest in if you have 1000 USD ?

100 times after 3 month? This is an incredible profit, please make sure that you are do it legally :). You can do if you want. I can tell you that there are something it's mind reach to that high of profit but you have to accept the risk of loosing all your money. The risk very high.
Option 1: Buy lottery every day :) --> Lucky will bring you to the Jack Pot
Option 2: Come to some Gambling house ( Casino ) :) --> this not allow Vietnamese and you need at least 20mil VND to come in ( it's depend on the Casino policy ).
Option 3: Do Forex or Gold trading using high leverage ( 1: 100 ) --> This very depend on you ability. For example Gold from 1000 to 1500 last time, using leverage 1:100 to buy gold at price 1000, you will able to buy 100 ounce of gold, as a margin account you are trading on, your purchasing power are going to reach higher and higher every day and that allow you to buy more if you want.
For example: 1000 to 1100, you are going to have 10.000 extra that allow you to have 1 mil USD buying power :) ( 1:100 again ).
Do it again, buy more gold, this time you have 1mil device to 1100, you are able to buy around 900 ounce more. WOW that huge :)
Take it easy and now just rest, go cafe, golf, networking... and see the money come and until price go up to 1500.
How much will you get?
You have 1000 Ounce Gold selling price $1500 per ounce. WOW You have 1.5 mil :D again 15 times than you expected :) but a little longer :)
Have fun and enjoy your life!

You guys should do more research about investment for more realistic questions and answers.

I think if you have knowledge about Forex Market, Analysis Skill, you should open an Forex Account, hogh return, of course high risk.
With 100.000 USD within 3 months, you are not ready for trading forex, you can authhorize us to trade and we pledge give an interest 3.5%/month, at the end of 3 months, you can withdraw your capital

Sorry that much money in three money. I have no idea. I want aslo to read other guy answer. Please share if you have any advice. Thanks

I consider gambling as a kind of investment. High risk, high return. 1000 times of ROI is (not?) so unrealistic but still too high :)