You're looking for glibness. That's a +20 untyped bonus to bluff checks made to lie, and it has a good chance to foil divination magic. Sadly it's a 3rd level bard spell only, so most casters (including yours) won't have access to it. You can get it in potion form for 1,050 gp. Pretty pricey, but it'll make you a god at lying for 10 minutes per level.
Those sort of spells tend to be for bards.
There's innocence (bard 1) which gives +10 to bluff to appear innocent.
glibness (bard3) which TheGreatWot mentioned.
compelling rant which is both terrible and awesome, but that's a 5th level spell.
assumed likeness, which is just weird. Also on pretty much everyone else's spell list except for cleric.
deflect blame is another decent one, but also not for clerics.
gullibility, which again is for everyone but clerics. Makes it easy for anyone to lie to the target.
So yeah, not for clerics I guess. A potion of innocence would only be 50gp, but that only lasts for 1 minute.
Someone with access to the Charm Domain could use the 1st level spell Ceremony to give a +2 Sacred/Profane bonus to a single Bluff check. Someone with the Glory Domain could give an untyped +2 to Charisma-based checks and if they augmented it, it could apply to 3 such checks.
Channel Vigor can give the caster a +6 Competence bonus on Bluff checks, among other things, but is a level 3 spell and only lasts for 1 round per CL.
Build Trust is a 2nd level spell. It lasts for 1 day per CL, but you also have to cast it on a particular creature. It's a +2 Circumstance bonus on Charisma checks and Charisma-based skills, though, and allows you to try to reroll if you flub a roll.