As has been stated the fish is a Flowerhorn. I realize ultimately if you have to ask than its more than likely a Flowerhorn. You generally can not look at a picture and go "Oh thats a Trimac you have there". Just running down the list in my head, all signs point against Trimac. You say you are from Sri Lanka and are not too knowledgeable on New World Cichlids, that right there tells me a true Trimac would possible be very hard to find there. Your neighbor India on the other hand has a decent grasp in the Flowerhorn world, so I would think the ornamental fish trade in India supplies Sri Lanka. You say you bought the fish as a Flowerhorn, that instantly tells you your fish is a Flowerhorn. Is it possible to buy a Trimac and its turns out to be a Flowerhorn, yes that is very possible. Is it possible to buy a Flowerhorn and it turns out to be a Trimac, no that is very very unlikely. So while your fish looks very Trimac like, so does the lowest grade Flowerhorn which are fairly common. With the information presented, I can say without a reasonable doubt that your fish is a Flowerhorn.
I have been in a similar position to you in the past except I bought a fish as Trimac and not a Flowerhorn. My fish was questioned and I wanted to believe what I wanted to believe. I understand the want to take the side of those telling you what you want to hear. But that doesn't make them right and it doesn't make your fish any less of a Flowerhorn.