Why hasn't he replied to me yet?

so there's this guy , the first day we met he kept staring at me and making eye contact without looking away and he kept smiling all the time , then I left the class we were in together for a month , and then i came back , he then just kept eye contact but without the smile , he looks at me then looks away and then looks at me and then looks away , he's in a talking stage with another girl but still looks at me deep in my eyes , I texted to him : hii , do u have private lessons in summer to teach? ( he's an artist so I was asking) but he still hasn't replied , 4 hrs , plus when I followed him on IG he didn't follow me (his account is public)

Updates
1 y
he left my friend on seen 30 mins ago and left me on delivered for 4 hrs
it measn he saw my messages but didn't open them
Updates
1 y
he also posted a pic of him 1 hr ago and I texted him 4 hrs ago
Why hasn't he replied to me yet?
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