[The Doctor is silent and deescalates in excitement a bit. He remembers telling Rose this - thing and he misses her. His face shifts to be looking more serious but with sad eyes]

I have a way of tricking death. Rather than dying, I regenerate.

[The Doctor is glad she remembers the quote, that tells him about when Ace is. And is rather sure at this point that this is her]

No, that isn't what caused that to happen.

[The Doctor stands more stiff and feels his hearts pounding in his chest. Because he is afraid of being rejected and it's completely understandable. Those eyes are for sure older than when last they met]