Hi, I have a niece (my sister's child) and she has a half-sister on her father's side. Am I related to her sister?

I just want to make sure whether I can date her?

You don't have a blood relation because you don't share any ancestors with her.

You can still be a good uncle to her though ;)

~ Tee

I just want to make sure whether I can date her?

--what's that saying.. "Don't sh!t where you eat"

My opinion is don't date her-- but that's just me...

How old are you both?

Sarah

There is no legal reason why you can't date her, perhaps age difference depending on her age

Hi, I have a neice (my sister's child) and she has a half-sister on her father's side. Am I related to her sister?

I just want to make sure whether or not I can date her?

If your neices sister is not to your mother then she is not your half niece but step niece.
Therefore she is not blood related.
If she is your sisters daughter with a different father than your niece then she is a half niece and blood related.

We are both 18, and my sister never got married to my neices father, they just had a child together. And since my niece shares blood with me due to my sister, and also shares blood with her father's daughter from a different mother (half-sister), then I should be related to her half-sister. But what would that make me?

So you are saying that your neices have the same father but two different mothers.
She would be your step niece and no blood relation even though she is still a half sister to your niece.

So you're opinion on me dating her...

Depends on how your family would take it I would think

But wouldn't that be incest because we are still closely related.

D00d, if you're this freaked out about being related to her, I would seriously reconsider pursuing a relationship with her.

If you're uncomfortable about it, she'll be uncomfortable about it... even if you two aren't related!

You aren't blood related.
You may have a hard time being with her because of what others will say but legally I don't think it is against the law.
You have to determine if you love each other enough that it doesn't matter to you or you'll never get past this issue

Many places do not even say it is against the law to marry your cousin.