Sameer started to like Naina, when he went close to her during bet. Then when he got to know her well and depth of her love for him, he started to feel guilty. The guilt was covering his mind. At the same time his liking for Naina was growing and the fear of guilt was capturing his mind.
Then at last his mind was thinking to confess about bet to Naina. But before confessing Naina knew about it and pushed him away. He was afraid to lose her. She became his friend, special friend but because of his sin he was going to lose her. She thought he betrayed her. This feelings made him think he does not deserve Naina and not to dare to think about loving Naina.
He loves yet his mind is not able to dare to accept that fact. He wants to get rid of the guilt of hurting Naina first. Just after getting rid of that guilt, the shadow of guilt covering his mind will clear away. And he will be able to see the depth of his own love for Naina.
Waiting for that day eagerly.