People complained that they didn't get anything but the proposal is rejected. Here are a number of strings that should be used for diplomacy for example when there is a rejection of a treaty.

MADLIB_RESTAIL_REJECT_SF ", but perhaps we shall reconsider your request in the future."
MADLIB_RESTAIL_REJECT_SF ", although we value your friendship."
MADLIB_RESTAIL_REJECT_SF ", though we hope to aid you in the future."
MADLIB_RESTAIL_REJECT_SF ", but we wish to see our friendship continue."
MADLIB_RESTAIL_REJECT_SF ", though we hope our relationship does not sour as a result."
MADLIB_RESTAIL_REJECT_WF ", although we mean no insult by our action."
MADLIB_RESTAIL_REJECT_WF ", though we hope you will not look on us with disfavor as a result."
MADLIB_RESTAIL_REJECT_WF ", though we'll surely help you in the future."
MADLIB_RESTAIL_REJECT_WF " because of some conflicting matters, which we cannot disclose at this time."
MADLIB_RESTAIL_REJECT_WF ", although we send you our best wishes for your future."
MADLIB_RESTAIL_REJECT_N " as our interests carry us in other directions at present."
MADLIB_RESTAIL_REJECT_N ", though we shall not rule out future considerations of this matter."
MADLIB_RESTAIL_REJECT_N " as your offer is insufficient to compel us."
#MADLIB_RESTAIL_REJECT_N " since we have other fish to fry."
MADLIB_RESTAIL_REJECT_N " since we have no need for that at this time."
MADLIB_RESTAIL_REJECT_N " as we are comfortable with our current arrangements."
MADLIB_RESTAIL_REJECT_WH " because of the insolence you have shown us in the past."
MADLIB_RESTAIL_REJECT_WH ", and warn you that future diplomatic requests of this nature will bring you grief."
MADLIB_RESTAIL_REJECT_WH ", for you cannot dictate terms upon our empire."
MADLIB_RESTAIL_REJECT_WH " as we have no fear of your bullying."
MADLIB_RESTAIL_REJECT_WH " since we are above your petty threats."
MADLIB_RESTAIL_REJECT_WH " since the time for peaceful relations has long since passed."
MADLIB_RESTAIL_REJECT_SH " and offer as an alternative your slow, painful destruction."
MADLIB_RESTAIL_REJECT_SH ", as we are busy plotting your destruction."
MADLIB_RESTAIL_REJECT_SH " and looks forward to spilling your insolent blood."
MADLIB_RESTAIL_REJECT_SH ", and warn you against future meddlesome actions."
MADLIB_RESTAIL_REJECT_SH " since we have no desire to seek peace with your kind at this time."
MADLIB_RESTAIL_REJECT_SH " since you are at best a fly on the butt of an ass."

Curse those money hungry accountants, probly rushed the game so these strings wasn't used.

I myself might look into it.