Having spent a lot of time around ebike shops, I can tell you that, as a general rule, that women do not find the same things appealing about an ebike that men do. That sounds sexist. I guess it is, but just being a male or female with a male or female brain is de facto sexist.
Only you know your wife and the sort of things that motivate her, but if she's like the majority that I've seen in ebike shops, she will want something that is easy to use, not one stacked with technical gizmos. A thing that often puts them off is a rush of power when they start up, so make sure that it has adjustable power. Assuming she's not too heavy (big assumption I know), any modern ebike will have enough power.
I'd be very surprised if she didn't like a Wisper Torque.
https://www.e-bikesdirect.co.uk/search/wisper_torque/?gclid=CjwKCAiA9rjRBRAeEiwA2SV4ZUorRLeuyyStmSQg1wKo38JDCa3675LDdbuw64iRchO7JHQLglKNLhoC0gIQAvD_BwE
I was in the shop a few days ago, where there was a guy trying out a 20" folding bike, while his partner was watching. I asked if she was going to ride too, to which she replied, "God no. That wouldn't do my street cred any good". I tried to get her to explain that, but she wouldn't expand on it.
