Is there any comfortable way to bring up this topic without making me sound like a narcissist who assumed a guy wants to sleep with her just because he asked her out🥲.

I wouldn’t say you sound like a narcissist but this does sound immature. “He wants to sleep with you” and “he just wants to sleep with you” are two different things. It sounds to me that he likes you and wants to spend time with you, and maybe-probably also wants to sleep with you. Is that enough for you? It’s enough for some people, though obviously not for everyone. Either way, talk to him about it.