"I had given you time."
Translation:Jag hade gett dig tid.
What is the different between 'jag hade givit dig tid' and 'jag hade gett dig tid' (both are accepted answers)?
I don't know but my guess is "givit" is more old fashioned and reltaes to the infinitive form "giva" and the present "giver"
That's correct, givit feels more old fashioned but there's no difference in meaning, it's just an older form of the same verb. (the infinitive and present sound even more old fashioned).
Couldn't "Jag gav dig tid" also be correct even though it's a different tense?
No, that sounds like 'I had given time to you' as if you had wrapped it in a package and given it as a gift somehow.