Certainly would happen x would happen certainly

Hello everybody!

It has been a long time since I ever stop to think about grammar and I've come to forget how to fit adverbs in the middle of the sentences. I would like to say : Isso é o que certamente aconteceria. But I have no idea where to put the adverbial "certainly".

This is what certainly would happen
This is what would happen certainly

Or is it on a different way?


Thanks in advance!
Happy Easter