I don't remember that quote, the only time she really talks directly to them is with Thalyssra asking how can we trust you won't succumb to the same things Azshara and Elisande did. I don't think that ever happened, but when about is that? Tyrande didn't have too many lines and the nightborne never really commented on their feelings about anything she said.
Nothing in game really from what I've seen, people usually refer to her talking to Thalyssra here:
"Archmage Khadgar says: Thank you for coming. We are here to discuss our mutual interests.
Tyrande Whisperwind says: Arcanist Thalyssra. I remember where your order stood in the War of the Ancients. How do we know you won't betray us and become the next Elisande... the next Azshara?
First Arcanist Thalyssra says: We do not intend to be slaves to the Nightwell. We seek to drive the Legion from Suramar and put an end to Elisande's oppression.
Tyrande Whisperwind says: The kaldorei will fight to see the Legion defeated and the Nightwell destroyed. Beyond that... we shall see where Elune's wisdom guides us.
Archmage Khadgar says: Thalyssra, your knowledge of the enemy will be crucial in the battle ahead. We shall call on you as needed."
https://wow.gamepedia.com/Quest:Take...eader#Alliance