Most Helpful Girl
Just keep talking on messenger he will ask you for your number when he's ready.
Maybe he likes talking to you on messenger? who knows besides a lot of people now communicate through social media rather than actual messages but just wait if he's into you he'll ask when you least expect it
Most Helpful Guy
One second. The guy may just be used to messaging through the internet or apps. The only reason why I wouldn't give my number to a woman I'm interested in is if I don't want her calling me.