Re: output is more than input. will it get confirmed?

So it mean I can pay 0 fee everytime I send BTC and it still get confirmed one day?

It is entirely possible. So long as a transaction is broadcast, there is always the possibility for it to be confirmed.

So how to STOP broadcasting it? Huh

You can't. You can have your wallet stop broadcasting it (either remove the transaction from your wallet or just shut down the wallet), but you have absolutely zero control over what anyone else on the network does. Someone else on the network could be broadcasting it, you can't do anything about that.

Your only option to "cancel" the transaction is to create a double spend which spends the same input but to an output that you control.

If anyone could explain me how to double spend using Multibit I will pay 0.05 reward

Based on their FAQ[1], Multibit will rebroadcast the unconfirmed transaction when the program is started. Theoretically, if you do not open Multibit for several days, the network will drop the transaction and it will not be rebroadcast.

I am not sure what seed generation method Multibit uses or else I can derive the private key and make a replacement transaction. You can try to stop and refrain from opening Multibit for several days and import the seed to another computer with a new installation.

[1]https://multibit.org/help/hd0.4/send-bitcoin.html