It says:
Kahit magmahal
Ka ng iba
mananatili parin
Ikaw sa puso
ko...
Rough translation:
Even if you love another, you will remain in my heart
Not used to seeing graffiti like this, but the person who wrote this might have been really aching, or needs an audience to hear him out, but still remain anonymous. Or he's a deviant who just ran out of dirty words and hometown love.
