Android is very specifically designed to put app data in the /sdcard partition. Asking it not to do that, or to trick it into thinking it's there when it's somewhere else will require root. I don't think there's any way around that. If this is something you want to do, we can help with that.
I am not sure about stock 4.1.2 from Samsung, but right around that version there was a change in the way the volumes are managed. Prior to that, volumes were static partitions within the device memory, but after the volumes are virtualized and dynamically allocated making total device ram available to apps and storage. If that version is using the virtualized volumes, then DirectoryBind will not work. (You'll lose your links with any reboot.)
Instead take a look at
Folder Mount to solve your problem. Of course, root is required here, too.
Now, personally I would try and avoid moving dynamic content like apps and databases to an SD card. They are slower and prone to failure when overtaxed. And when they go, there is little or no warning ... just *poof* .... gone. If you do move important content to an SD card, please be sure to clone the complete volume to either a PC or another SD card so if it does go south on you you have a working backup. (and don't forget to test your backup, too.)