40 turn long war or 15 turns war, 10 peace and 15 war

I'm going to assume the latter had diplomatic consequences, but how does that exactly work?

Assuming you started both wars, then you would have received a double diplo hit for aggression. Why did you take peace in the latter scenario?

If I'm going for a DomV and I'm besieging their capital they often offer peace, but I only take it if all of the following are true:-

a) my troops need a bit of healing
b) I will take the capital within 5 turns of starting up again
c) I have time to spare - i.e. I'm ahead of schedule as far as total capital sweep is concerned.
d) That breather won't allow them to reach their next key tech. I made a mistake once of giving a civ peace and he had musket when I restarted the assault. Not fun at that time, I promise you.
e) The monetary offer is enough to help me buy something decent in the 10 turns interlude, and/or get a WLTKD, etc.

If all are true, I'll do it. If not, I'll press on.

TLDR: It has diplomatic penalties for sure, as well as potential victory-diminishing penalties, IMO.

Thought so, cheers