Hi,
Not 100% certain, but I think that a soft reset will not "reset" your unlock code. If it did anybody could get into your phone.
You need to do a hard reset to reset the code. By doing a hard reset all your download apps and ''user data will be erased ''and the phone will be restored to a factory default condition. It will be like when you first bought it, thus protecting your data from being stolen.
Here is a link that shows how to perform both a soft and hard reset on your phone.
http://www.ukmobilereview.com/2014/06/soft-hard-reset-lg-g3/
Hopefully it is of some help.