heart beat

does your heart beat very fast when you see someone you like? Some say it will beat extra fast. whereas I heard a classic line (can't remember from which drama) - your heart can't be beating at 100+ all the time. You need to find someone who lets your heart beat normally and yet feel comfy with him.

Then how do you know when you like someone? For me, i guess he did not make my heart beat faster. He just make me want to look at him more, smile at him more, talk to him more. Is that called drawn to him?

Then how do you know if he likes you in return? My friend told me if he likes me, he will sms me within 3 days. If not, i can move on. I hope he will sms. Our hearts will beat at the same pace.