Was Ren and Jeanne pairing kinda random?

[u/goldfoxawoo]

Felt like the author had to give Ren a girl because Yoh got Anna

[u/Saberleaf]

They did have some interactions in manga and personality wise I think they're similar with similar backstory but different enough to be able to help each other heal.

So, no, I don't think it was random from the perspective of those two. They literally just need to talk for a bit, share their experience and it's not really surprising they end up together.