Amir is selfish and Hassan is humble and loyal to Amir. Hassan is a Hazara, Amir is a pashtun. Amir is granted to right to get an education, Hassan is not.
Actually, they are half brothers. Amir had found out that when Rahim Khan had hinted that Ali was not Hassan's father but Baba was (which explains why Baba had a closer relationship to Hassan and Amir).
Amir frames Hassan for stealing money and a watch, knowing that Hassan will take the blame to protect him. Amir stands by and does nothing to stop it, thus indirectly getting both Ali and Hassan in trouble.
Amir threw pomegranates at Hassan out of frustration and jealousy stemming from their complex relationship and his own insecurities about his father's affection for Hassan. This act was an expression of Amir's conflicting emotions and desire to hurt Hassan in the heat of the moment.
Amir placed the money under Hassan's mattress to frame him in order to rid him for good. However, when Baba asks him if he stole the money, he shockingly admitted to it. Despite Baba's thoughts about theft, he is still willing to accept Hassan as part of their family; (SPOILER ALERT: because we soon learn that he is Amir's half-brother.)
Amir and Hassan, the sultans of Kabul
Hassan and Ali give Amir a leather-bound notebook for his birthday.
Hassan's first word is Amir. Amir does not reveal his name till this point, which shows his underlying guilt because Hassan loves him so much and Amir's betrayal.
Amir put his watch and some money in Hassan's mattress. Hassan found these items and told Ali about how he got raped while Amir hid and watched, so they left Kabul.
Baba shocks Amir by letting Hassan and Ali stay at the house, as Amir had put the wristwatch and Afghani bills under Hassan's mattress so that when Baba did find out about Hassan's stealing (a trait that Baba once told Amir he would never forgive in a person), Baba would want to push them out. Instead of Baba kicking them out, he forgave Hassan for "stealing" (he only admits stealing from Amir to protect him), and begs them to stay. Hassan and Ali leave the next morning and Baba weeps when they leave.
well i don't know three.. but i know one seeing as I've only had to read till chapter 5 so far but 1. when Baba tells amir to ask hassan to go with them to the lake..Amir says Hassan cant but in reality amir didnt want hassan to go because of the last time when hassan skipped a rock 2 times more than amir and baba praised him for that and amir didnt like that.
Hassan is Amir's half brother. Hassan's father, Ali, was like a brother to Baba so he lived with Baba. However, Baba impreganated Ali's wife and had Hassan who became good friends with Amir.