Exactly what is your wife afraid of about trying ToT? I love going on it, but my DD (16) doesn't like it. She went on it twice and now that they change it and you don't know how many times you will drop, she won't go. She doesn't like the drops. She also doesn't like Dinosaur (too loud). We finally got her to ride BTMRR within the last two years. She wouldn't ride that because it threw her around too much. Now she loves it. DD didn't want to try TT and now it is her favorite ride.
If she is caustraphobic, it would be difficult to convince her to go, if she isn't, then it might be easier. You might have to compare it to something that she does like.
I really wasn't too thrilled about the bit of "airtime" I would get when they had the lap bars, but now they have individual seat belts for each seat.
I have a small fear of falling and this ride does NOT bother me in the least. I didn't use to have this fear until I went to Ireland and kissed the Blarney stone. (Upside down over a 3 foot gap, at least three stories above the ground). But the only time I have ever regretted doing it was when I did Tot, RnR, & Star Tours one right after the other - I don't recommend that at all.
Find out exactly what her anxiety is about and then go from there. Once you know why she doesn't (other than just very unsure), then you can look at easing that particular fear.