I would be paranoid too. The biger company the more.
It's a problem elsewhere in the world too, but many Filipinos are "experts" at copying
when not earning at it too. (=Copy and start similar to close so everyone get to few customers.)
You can get SOME protection by make a proof you made it BEFORE you showed it to them, AND get a proof you of what and when you are showing it to them.
I don't know any reliable such, but there are agents and "connectors", between developers and possible buyers, who can be witness if the possible buyer try to take it.
You can SHOW the USER INTERFACE to the possible buyer, WITHOUT showing them the CODE. Then they can still try to take the IDEA, but they would have to make all the CODE themselves, so that's SOME protection.
I don't know if the Philippine patent and copy rights register can protect you. I believe NOT. Such is just KIND OF a protection in LAW point of view, BUT such registers are PUBLIC, which make it EASIER to take it
and just make some change to get around it, so in most cases I'm AGAINST spending any money and time at trying to get such protection. But in some cases it can scare away some copyist.