diplomatize

verb

Etymology: From diplomat + -ize.

To engage in diplomacy.
“Without diplomatising to do so, with no effort to square her, none to bribe her to an attitude for which he would have had no use in her if it weren't sincere, he yet felt how he both held her and moved her by the felicity of his taking pity, all instinctively, on her just discernible depression.”
To effect by means of diplomacy.