Do you think hes interested in me?

i went to a bookstore a few weeks ago and while walking over to look for a particular book, i felt someone looking at me. glancing up i saw one of the workers looking at me. he was very cute. i kept going because i really needed that book. later, while sitting on the phone, he walked by and we made eye contact for a while. he would walk by every now and then while i was sitting reading. when i left, he was by the door. "u leaving?" he asked and when i said yes he was smiling really hard and said "u coming back tomorrow?" and i shrugged and said "maybe" and left. i did go back the next day with my sister, but i didnt see him working that day. about two weeks later i went back to look for a book and he was there. when he walked by he glanced at me (i was reading) and kept walking. when i left he was by the door and said "hi". i said "hi" and hesitated and kept looking at him, giving him a chance to speak, but he didnt say anything else. when i left and looked back, i saw he was looking back as well. i went back the next day with my friend, and he walked by slowly. when we left, he was standing by the door and opened to door for us (since the store was closing) i said "thank you" and he said "good night" softly. then he said good night to my friend. once again i looked back and he was looking. then he stopped. at first i was confident he was interested (after the first time) but after that he had multiple opportunities to say something but didnt. do u think hes interested? how do i break the ice? i dont know what to say!