If we go by record, only a few boys have shown interest in Naina, and there name usually starts with letter "s" !!
Sanjay Tibrewal
The first boy to have shown interest in quiet and introvert Naina was her equally studious classmate Sanjay. He was instantly attracted to Naina, thanks to her new hairstyle. Being introvert himself, he still mustered the courage to propose to her and wrote her a love letter, which was caught by her family. As a result, her family forced her to tie a Rakhi to him and his first love became his sister.
Though he moved past his initial feelings, he didn't move on from the insult he had to face from others.
He instigated Sameer further against Naina and supported Sameer's bet(which became Sanjay's way of revenge)
However we can say that he had a happy ending after all, when adult Naina shared that she still sends him Rakhi, indicating that he no longer carries grudge against her.
Sameer
The Salman Khan of Ahemdabad met the Behenji Naina when he was busy in teaching a lesson to a boy. His initial impression of her was spoiled when she complained against him and their further conversation was based on his feelings of revenge. She soon entered his worst list of enemies, when he was wrongly accused of stealing the papers. He made a bet against her, made fun of her and tried to cause her insult. During all this, the innocent Naina fell for the inner Sameer and mistaked his fake love to be true. However, Sameer soon started understandibg the real Naina and moved past his initial impression of her. He started valuing her unconditional love and care for him. But, he soon caused her heartbreak and as a result, faced her hate and indifference. He still stayed strong when he realised his own unconditional love for her and tried his best to win back hers.
Sameer came a long way since his school days. From being disgusted at the thought of him being married to the Behenji, to excitedly planning their future life and his family's wedding proposal for her, he changed a lot.
He became a knight for her and got into fights for her on more than one occasion, not caring about the impact it might have on him. He transformed into her pillar for support and stood by her, be it school debate or elections. He never let anyone question her dignity and acted as a wall to all those who might cause her harm . Sameer refused advances from all other girls, except when he wanted to make Naina jealous because he could no longer see beauty in anyone except his jhalli and Behenji.
Sharad
Sharad was immediately attracted to Naina, when he came to see her. He wanted a modern, beautiful yet a agyakaari wife. He convinced her family to let them meet alone and our impression of him was immediately spoiled when he praised himself repeatedly and bossed on her. He even showed that his "yes or no" matters of lot and her own opinion does not matters at all.
Sharad was a disrespectful ,arrogant and narrow minded guy who could not tolerate his fiance or her family speaking to him. He did the ultimate wrong when he insulted Naina in front of whole college and slapped her. He tried to raise his hand on her again, only to be thrashed by her knight in shining armour. Sameer warned him against raising hand on his Naina ever again. Sharad could not tolerate this and instigated Naina's chacha against her, only to be slapped by her in front of his mother.
No matter how much we hate him, the character of Sharad was important since it showed the true nature of 90's patriarchal society and the position of women in the era. Unknowingly, Sharad made Naina realise the worth of Sameer and the position he holds in her life, the position that she could not give to anyone else and the position of her in his life, which she could not share with anyone else.