How to convince her into swinging

Communicate with her, that includes really listening to her. Make her feel safe in your relationship, safe sharing fantasies. Make her feel desired by you, because if you don't make her feel desirable she may not think others will find her desirable. Have a really good sex life.
 
Communication is everything. Have a conversation around swinging and work your way up to it. Try a swinger club, they are a lot of fun. Set boundaries and make sure your wife knows it is not expected that she has to play. Sometimes getting into a swinger club and seeing how it all works and meeting some members is a great way to break the ice.

My wife was hooked after our first time. Now she loves the couples side and the single side in the playrooms.
 
Communication is everything. Have a conversation around swinging and work your way up to it. Try a swinger club, they are a lot of fun. Set boundaries and make sure your wife knows it is not expected that she has to play. Sometimes getting into a swinger club and seeing how it all works and meeting some members is a great way to break the ice.

My wife was hooked after our first time. Now she loves the couples side and the single side in the playrooms.
Constant communication even once you start , checking in that you both are still on board, any adjustments to your rules/guidelines, what is working, what isn't, what else either of you might be interested in, etc etc etc