How to convince my wife that we should foster?

For a long time now I have felt very deeply that I should be a foster parent, practically, socially, spiritually, economically, and in every other regard I am ready. This is my calling. But my wife doesn't feel ready and I wonder if she will ever feel ready. I've been working with youth and children through church, scouting, and other mentoring groups. I worked with some pretty tough kids too with a wide range of traumas. Even before we were married, I had mentioned that I wanted to help children, and we talked about fostering before we had children of our own. Our first kids, twins, had some serious health problem early in life. We certainly paid our dues. We struggled for a few years while I went back to school and we were broke living on charity. We relocated to Silicon Valley and I got a fantastic job, the health problems miraculously went away and we had another child. Things were great. We decided that we were ready to give fostering a try. We connected with an agency and made friends with other foster parents and children. We read books and did all of the training required, got a spare bedroom ready, and everything required. We were one interview away before being matched with a foster child and my wife backed out. I was sure that it was something we could talk through and get right back into the program, but it turns out there were some very deep concerns. My twins were now 5 and were starting to develop some attitude and even acting out violently and sexually (there was some hazing going on by a neighbor kid). My wife was feeling overwhelmed. As new parents, I think we both had to admit that our parenting skills had much to be desired. We found ourselves shouting and arguing, and even some spanking that we weren't comfortable with. I realized that I was spending a lot of time working and commuting which left my wife with a lot on her plate. The elementary school situation was not good in our area and we chose to home school. The first year is pretty challenging. Ultimately, my wife felt that she was barely getting by and that if she couldn't handle our own children, how could she bring in a foster child to the family. I keep bringing up the topic when I feel like the time is right, but keep getting a no from my wife who still feels inadequate. So, it's been a few years. Life has been great. We added another child to the family and my wife has decided she doesn't want to be pregnant ever again. I've been able to arrange my work priorities in a way that has allowed us to thrive financially and give me more time at home. As parents, in my opinion, we have made a lot of progress with our parenting skills, being more positive with more realistic expectations. We are giving up the rat race of Silicon Valley and moving to rural Utah next month. We will have a large home in an excellent neighborhood nearer to family and our support network. We've got the homeschooling thing figured out (although we might start kids in public school since the neighborhood is so great). Our children are perfect :grin:. Perhaps I can get involved with the fostering program initially in some administrative ways. I think now is the right time to try and bring up fostering with my wife again. We've got a babysitter set up and the opportunity to make a romantic get away soon. How can I help my wife see that she has achieved so much and overcome challenges and that she is more than adequate to be a good parent to our own or any child for that matter? We both feel that fostering is good, but I feel like her lack of enthusiasm and kicking the can down the road will start taking its toll on our relationship since I'm so passionate about this.