well from my personal experience:
Its just like Sajan story and he is sammy and I am gunjan in my story...
We are best friends, very special friends. It started out with getting help from him in some subject to an allniter and to coffee run and wrong phone calls and then hanging out with each other more often and then doing everything together. Its like meow and rats from JTYJN. We know each and everything about each other. When he was in college with me, we spent sooo much time together that we didnt even care to see others around us. And slowly I started liking him and i didnt even kno. I liked how caring he was, how he was the first guy to understand and help me thru any prob of my life.
And coming to question on how do u know when u r falling for someone is well when u start dreaming about that person and life with that person. U wanna spend each and every moment iwth that person. U always wait for his call and when he doesnt call u get restless. U wanna call him just coz he hasnt called u. U feel like day wont pass by if you dont hear his voice even once. U get jealous if he is praising other girl or checking someone else out. U get possessive over him. PPl around u start assuming that theres something goign on and u kinda starting liking that too. U care soo much about him. U do things that u wouldnt have normally done for anyone. U credit him for everything good happened. If he makes fun of you, it hurts initially but then you like it. There are certain nicknames that he would use (some friends do) and u would want only him to call u by that.
Something wrong happens between him and u, it will make u annoyed and frustrated because u miss talking to him and u miss even more when u r not on talkingn terms. U cry over him, for him. U would only think his pranks and jokes are funny and justified.
There are lot of things
sigh*💔
Unfortunately he didnt like me in that manner or for him love doesnt exist💔