Definition of "tenderest"

This intimacy did not decrease with further acquaintance. I found Lischen the tenderest of nurses.

1844 January–December, W[illiam] M[akepeace] Thackeray, “My Pedigree and Family.—Undergo the Influence of the Tender Passion.”, in “The Memoirs of Barry Lyndon, Esq. [The Luck of Barry Lyndon.]”, in Miscellanies: Prose and Verse, volume III, London: Bradbury and Evans, […], published 1856