Over the last 7 years I've tried buying lingerie for my wife. It started as a 'gift' for me but she never seemed to be comfortable wearing it and after an initial appearance it would be lost to the bottom of the drawer. Since then I've made more and more purchases aimed at buying something to mix arousal with something she felt confident in. I still don't seemed to have cracked it and I haven't been buying anything to extreme, just nice chemises and babydolls.
How can I help to make her feel better about wearing lingerie, she knows I love it and that I find her amazing in it but maybe I'm missing signals and should just forget about it.
And I mean openly and honestly. Simply on a nice night when you're cuddling on the couch or something asking if she likes dressing in lingerie and what types. If not, why not. Maybe ask her if she wants to buy some with your money rather than you buying. the main thing though is not to make her feel bad for not feeling up to it. the main reason is most people (male and female) are very self concious about their bodies and can feel really daft trying to look sexy. It's likely she feels foolish trying to be something she feels she's not.
and it's not something easily fixed. Don't expect one night's chat and suddenly she's coming back from the bathroom in a latex dominatrix outfit. See if she'll wear a nice nighty or fancy normal underwear and work up. It's all about her feeling comfortable and sexy and that's only going to happen if she believes it.
oh, also, instead of "lets buy you some lingerie", why not go out to a party in fancy dress. BOTH OF YOU. that way being a bit silly isn't so daunting and you might be able to encourage her to wear something sexy underneath for alter.
good luck. an ex took a big step in getting a maids outfit once. She walked in, and before I was able to react promptly burst in to tears. A bit of talk and encouragment and there was other outfits bought not much later and she started to love dressing up.