That's nice symbolism U picked up there :-)
I feel the laal/red rang/color which he puts on Zoya is symbolic of his love which will never be erased from her heart. The color of his love has fallen all over her.
But at the same time I think it indicates blood or fire which means she us going to colored in blood soon too with Razia in the background that seems likely.
I also feel like his love for her might be the reason for her being put in danger. (maybe tannu tries to kill her?)
I agree with your interpretation. I was thinking in the similar terms and also as someone mentioned too it may also mean Asad might not completely agree that he is in love with Zoya. Instead he will definitely make her feel that he is in love with his actions. Why because if it is a confession it would have been an another maha episode. I am sure when it is time to confess that Episode promo will be even more special. Another thing I also noticed was Zoya was kind of sad and walking away from Asad and it was clear on her face but it changed when he put the red color on her face and they both started smiling looking into each other's eyes.
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