How do I pronounce the name Sena?

I'm having trouble with the 'Se' part of the name. I try to pronounce it like the beginning of 先生. In English it is closer to the pronunciation of 'set.' But, I've heard people pronounce the name like 'Say-na.' It sounds off when people do this, like the name becomes Seina (せいな).

It is driving me nuts. I usually feel confident with my pronunciation, but this name is making me question things! And it is for a boy.

Any help would be appreciated.

I've heard people pronounce the name like 'Say-na.' It sounds off when people do this, like the name becomes Seina (せいな).

That's the way that native English-speakers typically pronounce it. If you ask a Japanese resident in Japan, most people will pronounce it as せな. There actually is a Japanese sirname of that spelling (such as 瀬名).

Try pronunciation sites like these. At least this one is very accurate when you type in "Sena" (in alphabet) and let a "Japanese" say it.
http://free-translation.imtranslator.net/speech.asp

But if you're talking about people in America, yes, a lot of them will pronounce it kind of like "seina". Consider it as a nickname.

I would pronounce it like the last name of the late Formula One driver Ayrton Senna.

Thanks for the responses! The pronunciation website is a neat tool. Had a bit of fun playing around with it. I also talked with the kid about the pronunciation of his name. He's cool with the way I say it, so no need to change. Needed the feedback before I could get the courage to ask him about it! Thanks again.