Vasectomy reversal

My fiancé had a vasectomy November 2018 after having 4 children together. We have now decided that we would like to try for one more, I’m really nervous now though as I’m getting my hopes up and I’m scared the reversal won’t work. He’s thinking of getting it done at the end of the year, making it 2 years since the initial procedure.

Anyone else dealt with a reversal? Any advice?