Secret Shop Won't open.

Just to tell you. If you gift him too much, he'll start to get annoyed. Also considering his difficulty, you may have to carry items in a bulk, instead of giving small quantities. Are you even using your keywords?

Edit: Not sure why I'm adding this.

My experiences with secret shops are quite fun, after playing this game roughly 5-4 years. One of the things I noticed is, it's more effective to carry 30 gifts, rather than 5 at a time and running back and forth to give 30 gifts. As a noob who wanted to open both shops for the books, you can already see how much I would succeed, because at the time moon gates were open randomly at night, I didn't have free mounts nor did I have the biggest inv. I ended up storing some gifts in the bank for Nele and by the time I opened Stewart's, I got an event bull.

NPCs seem to really hate it when you mass feed them gifts, or get annoyed that it took me 10 seconds too long to get the gift out of my bank. D:<

I know about that. I know they get annoyed. But I did the private stories and he gave me the option to buy membership but at the time I didn't have enough money. Now he won't give me the option to do it. Do I give him more wine?

So it did work...you just messed up at that point basically...

Yup, redo. NPCs don't keep their like for you forever sadly.