My trunk latch will not stay closed, is it fixable or do I need to replace

Hello, The latch assembly for nearly every vehicle will not be serviceable, so replacement would be the option. You should check to make sure the emergency trunk release or trunk unlock switch inside are not sticking and causing it to remain in the unlocked position. Also, if slamming the trunk hard works for you, the latch, striker, or trunk lid position likely needs to be adjusted. None of these items are difficult, especially if you use the technical manual and have Torx bits.