She will get it and do it, when she is ready.
My son, was already 3, once 'he' was ready.
We did not force it or push it or lecture him or ploy him with things.
Once he was ready, he was ready... then HE was proud of himself.
Not because we gave him rewards or toys or M&M's for it.
Your child... ALSO is NOT ready... for just being in underwear.
It goes in stages.
She cannot control her impulses yet nor her bladder or bowels.
Underwear, does not 'make' a child potty trained.... especially if put in it, before they are even mastered at the potty or ready for being on the potty.
With both of my kids... I did not have them in underwear inside or outside of the house... UNTIL they were mastered at their biological impulses and KNEW their bodily cues... AND could hold it... at least a couple of minutes until, getting to the potty or toilet.
If you do these things TOO soon... you will sabotage, them.
Then they will think, they cannot do it right nor please Mommy.
Then they may not try at all.
And/or rebel about it.
Your child does not seem ready nor has the biological readiness... nor the timing... of her internal organs, ready yet. Hence, she has accidents.
Keep in mind... that night-time dryness... is a whole OTHER process and is totally SEPARATE from daytime pottying.
Night time dryness is a physiological maturing of the organs/brain/myelin nerve sheath and bladder/bowel development. Not that age of the child.
Night time dryness... is something that does NOT occur... until even 7 years old. And is NORMAL.
Until then, a night time diaper will still be needed for naps or bedtime.
My son is 5, potty trained by now, but at night and for naps, he still needs a night time diaper. He is still wet at those times.