Ajeeb Is not the Word - Ajeeb means Weird. If You say
"Tum Bahut Ajeeb ho" - You are very Weird - He or she may take offense of that.
If You wanna say that some one is funny becaudse their talks make you laugh always You can say
Tum Bahut Mazaakiya Ho
Mazaak - Kidding
Or for someone who is always smiles or of pleasant nature you can say
Tum Bahut Hasmukh ho.
I Like You a Lot
मैं तुम्हें बहुत पसंद करता हूँ - Main tumhe bahut pasand karta hoon
and karti Hoon if Female
You are Very Cute - You can say Cute too
Tum Bahut Cute Ho
I will come fast in a sence of I will come soon?
Main Jaldi Aaoonga - I will come soon
Aaoongi if Female