They married for political reasons. Not bewitching.
Konoha has always had more ambition and been more bold than was obvious. Marrying Sol gives her more power and status that she can use at her own disposal.
For Sol, becoming the pope's heir pushed him into this position. He probably could have rejected the marriage if he really tried, but he could never go back to being Sol, Iana's butler. Accepting the marriage puts him in a position of power.
I'd also wager they intend to expose the church from the inside.
I think it's a really interesting and complex decision.

So...are they getting married for politics...or bewitchment..??? I mentally check out when I see sol. What is going on, why did they get married again, cuz the plot has always been plotting but I hit a brick wall with this sol x priestess arc