This page is not precise, it has been data I've gathered from TW forum and gamefaqs:
#1 Factors Edit
A lot of things factor into a successful recruiting attempt:
- how well they like you
- how well they like their current liege
- your reputation
- your right to rule
- your persuasion skill
- available fiefs in your kingdom
- your choice on why they should join you, explained deeper in #2
And probably dozens of other, minor factors.
#2 Options Edit
When you ask them to join you they'll talk about four different things:
1) Their safety should they join you. Edit
This is affected by how large your military is, and whether or not your Kingdom is close to fiefs they own. In other words, if your Kingdom is pushing on their borders they'll be more likely to say something along the lines of "I'll be safer with you."
2) How much they like you. Edit
This is based on your Honor rating and what company you keep. If you have a lot of heroes and Lords that are honorable, it's easier to recruit honorable Lords. They'll usually say something along the lines of: "I like you and your companions more than the king." if they like you "I'd have better standing in my current liege's court." if they're neutral and "I dislike the king, but I dislike you and your companions more." if they don't like your company.
This is also affected by their "friendship" rating thing to you. You can increase this by fighting them and then letting them go, or doing quests for them.
3) The promise you make them. Edit
One important note, BE CONSISTENT. Don't promise one guy that you'll support the common people and the next guy that you'll support the nobles. They'll know and remark about it. Now this one is most complicated because it is affected by both the choice you make and each choice is affected by different things.
Each lord will prefer one of the choices, it should be pretty clear which one after you try it out the first time. They'll mention something about it on this third block of text.
i) I should be King by old laws. This is affected by the right to rule rating. The higher the better. Around 40 is when they start agreeing you deserve to be King. Before then they scoff at you.
ii)Support commons/Nobles. These two are aren't really affected by anything, but make sure you stay consistent.
iii) I will unify the land It's probably affected by how much of the landmass your kingdom encompasses. The more fiefs you own, the more likely they'll agree.
iv) I'll give you land. I figure this probably is appealing to Lords who have no land of their own. You can check in the notes who has fiefs and who doesn't. I hardly ever pick this.
4) I'm not really sure what the last one is based off of. Anyway if they say "I could lose a lot of my reputation." That's the bad response. If they say "But my men will understand." That's the good response. I think its based off how large your Kingdom is and your Right to Rule since it makes sense that if you don't have a large Kingdom/ don't have proper claim to rule then the benefits of joining you aren't worth the risks.
I usually don't ask them to join me until at least three of these are good responses. Even then sometimes they say no. On the other hand I've had a guy join me when he had 3/4 as negative responses. I think there's an element of chance in there as well. Anyway hope that helped a little. Just keep trying and you'll get someone eventually.