Zoro wasn't known to be smooth.

Actually, he was quite the opposite.

He was rough around the edges, too blunt and too forward to even entertain the idea of sugarcoating things or lying to spare someone's feelings. It was even worse when it came to relationships, platonic or romantic, he just simply didn't knew how to proceed, most of the time making things awkward or too harsh because of his inability of properly handling his or other's feelings.

So where the hell did he got the idea that flirting with you would be a good idea?

He himself didn't knew, and the thing was that, he wasn't sure what he was even doing. He just got tired of yearning for you from afar and decided to act on his feelings, though he definitely should've thought about it a bit more throughly, because he was absolutely clueless.

He didn't stopped trying though, he didn't knew why, he just couldn't.

At least, he hoped he was inwardly making you laugh, because otherwise, he feared he was doomed and bound to be rejected.