For what it's worth, I've dated several people who initially said something like "I don't like being tickled," but who then ultimately ended up finding a way to enjoy it once we talked more about it, and they understood the effect it had on me. Like, plenty of people have submissive/sadomasochistic tendencies more generally, and can find pleasure in stuff like spanking, nipple clamps, post-orgasm torture, etc. It's "painful," but when it occurs in the context of a sexual/romantic relationship with trust and respect, it can be an "enjoyable" pain. Just so with tickling. Some people might "not like being tickled," but might still enjoy the experience of being restrained and tortured by a partner, if they appreciate how much their partner is getting off on it. Maybe it's not something they're comfortable with all the time, but it might be frequent enough for you to feel satisfied. Obviously I'm not saying everyone is like that, nor that anyone should be expected to react that way. Just that it's a possibility worth exploring.
That being said, if you've thoroughly discussed it, and she understands and respects how much this matters to you, and it's still not something she can find a way into enjoying at all, well, that's a pretty major incompatibility. You might also think/talk about the extent to which the two of you are comfortable with various forms of non-monogamy, and whether that could possibly be satisfying to you. Though of course, it sounds like you mostly want to tickle her. I'm not going to tell you how to weigh your priorities, but for me, I know I could never be long-term satisfied with someone I didn't feel sexually compatible with. So if someone didn't and couldn't enjoy being tickled, that would definitely be a deal-breaker for me.
