2 Ninians !! which one should i choose?

As dancer her primary role is to give her turn away so any set of IVs is viable on her...but in this case one is clearly better than the other.

In my opinion +ATK -DEF is the better of two meh options. You really don't want -SPD for her under any circumstances. Keep her even further away from physical attacks than you usually would and maybe slap lightning breath on her so she can trade with mages. It has the added perk of netting you an additional point of BST (ATK goes up 4 instead of 3).

Shes a dancer so her ivs are not that important.
Those are super bad ivs on her tho. She can still be useful in a pinch if u give her TA to at least tank some hits for that ud want the + atk one for more offensive but the +hp one since she will most likely be doubled anyways so u can be bulkier

Ninian is a dancer, so she won't be in combat often (hopefully). That said, she might be forced to defend herself or her carry on occasion, so you will want to make her as resilient as you can. Triangle Adept can be taken to secure her matchup against red units, although she still won't be dealing earth shattering amounts of damage. Otherwise, Fury significantly improves the dragon's survival against red and blue.

If you're going to use TA, you can get away with using the +hp -spd variant so long as you can cover Ninian from blue and green units. However, Falchions can still destroy Ninian unless she also brings Swordbreaker, so be aware of that.

Fury Ninian can't afford a speed bane, as many things that double her will prove fatal.

That said, I strongly recommend the +Atk -Def variant for any build whatsoever you will use.

Definitely +Atk -Def -- that's the sturdier IV, believe it or not. -Spd will get her doubled and killed pretty frequently

That said, dancers are rare and immensely useful in GHBs, so unless you already have some extra Olivias and Azuras lying around, don't get rid of the -Spd one.