Gifts not working?

[Nebuchadnezzar]

You need to do this very early in the game and its not likely to succeed. They are your natural enemies. Are you at war with another faction that has an alliance with them or vice versa. If so your relations will drop over time and it may not be possible for an alliance. You will also need a very high global rep to maintain the alliance.

Consider a marriage proposal with them. This will provide an automatic alliance and greatly improve your relations with them. You need to plan ahead to do this though and keep rejecting suitors offered for heir/FL at start of each turn until you spot a suitable Spanish princess preferably with 4+ hearts. And/Or use your princess to marry into them if possible. Marriage alliances are generally stronger and likely to hold longer. Multiple marriages is better still.

Normally with an alliance your relations should improve slightly every turn so there shouldn't really be a need to gift unless you need a quick boost. Its generally a good idea to exchange access rights with any faction you have allied. If you don't then your relations will drop quickly if either cross into each others territories.

Spying/bribing or assassinating damages relations and in some cases rep.

[TheSeated]

It's like turn 20. I'm not at war with anyone but the Rebels, and I havent sacked any cities or killed any prisoners. I married Prince Rufus to a French princess straight away, so I am allied to France. I like the challange that VH/VH brings as I believe the AI plays alot better on that setting. Im just shocked that 8 turns of 100 fl tribute on top of 8 turns of 1000 fl gifts havent moved my relations with Spain passed reasonable.

From the FAQ:

"Finally a note for those playing on Very Hard. Your relations automatically degenerate towards Abysmal (-1.0) every turn at the rate "normalise -1.0 40".

I believe this mean if you have Perfect relations with someone that your faction stand with drop by 0.05 the next turn and at a slowly decreasing rate every turn. So you should be able to stabilize this affect with a 100 fl gift every two turns."

Something else is going on here and Im not sure what or why...

EDIT:

Ok, so I cheated. I restarted the campaign, gave myself 100k florins and plopped my diplomat down next to Toledo on turn 1. 1000 florins for an alliance was generous but unacceptable, so I used the exploit of offering the same deal over and over until our relations were perfect. After our relations were perfect they still wouldnt accept an alliance for 10k florins! It took 20k to get them to accept the offer! wtf?!

[CountMRVHS]

I suspect it might have to do with the AI faction's priorities. When you enter diplomacy, there's a "priorities" section near the top. It will say something like "peace", "war", "trade", etc. It'll say "unknown" if you don't know what their priorities are. My guess is that Spain is more interested in fighting you than becoming your ally, and having better relations might not make them willing to actually ally with you.

Also, what is your global rep and overall strength? Those might be factors.

[Nebuchadnezzar]

From the FAQ:

"Finally a note for those playing on Very Hard. Your relations automatically degenerate towards Abysmal (-1.0) every turn at the rate "normalise -1.0 40".

I don't believe relations are affected but your global rep which will drop a bit every turn when playing on VH. This is not the same as your relations.

Its really not a good idea to ally with a neighbour as it will be near on impossible to maintain with the games current diplomacy system which being near on meaningless.

If you still want to ally do it within a few turns (ie less than 8) they are more likely to accept or use your starting princess. Also work hard to improving global rep to at least Very reliable or preferably trustworthy. To do this you need to occupy all settlements and release all prisoners but you have to be at war with somebody first. Its the easiest way to offset the neg effect of VH.

Being at war reduces global rep a tiny bit each turn and being allied a tiny bit improved. You also shouldn't use assassins and never loose an ally whether your fault or not b/c this gives a very serious neg affect for global rep. Also with allies you need to exchange military access to ensure relations don't drop as the AI tends to trump around all over the map. There are a number of other important tips also here & there.

[Gaiseric]

Lol, diplomacy and diplomatic relations in this game are a sham. That money you gave them could be better used to build armies and improve your economy. The only faction that you have to worry about giving tribute to is the Papal States. Give the Pope that kind of money every turn and you can go to war with your catholic neighbors, and not have to worry about excomunication.