Regarding the request to declare war. Thats a dialog between you and country A. Country B would only be aware if you accepted the deal and declared war. You could tell country B "Hey your enemy wanted me to kill you...but I didn't." But thats not really a compelling way to make friends. Far from showering you in praise, such speech would be very unnerving. It would more likely leave them thinking "So, you were considering allying with my worst enemy? Is this a threat?" Just no logical way around this. You don't make friends by not being a homocidal maniac and bragging about it.