I dont think it is manipulative to try to understand that what SHE might find attractive about cruising arent the same things that I might find attractive. Trying figure out what's in it for your partner and then trying to give it to them is good advice for anyone on land as well as on the boat.
For my part, I was very upfront with her. I told her I was obsessed with sailing and would love it if she learned to like it too. Being a total landlubber, it was never going to be something she came up with first. I asked her what she thought sounded good and what she was afraid of. I told her I would NEVER try to push her out of her comfort zone but that if she would give it a try I would do whatever I could think of to make it a good time for her.
I dont know. Maybe that was manipulative. I certainly said things like "The cruising guide says there are good shops for summer clothes at the next port so I am going to bribe you by giving you money to buy some" She could (and sometimes does) say things like "Thats great but what I really want is not to heat the boat up by cooking dinner on board tonight" Nothing I did was ever a secret plan but it sure as hell worked. It turned out that what she really wanted was to be warm in the winter. I could certainly live with that though my original idea was cruising closer to home. Her fears were real - she really was completely ignorant about sailboats - and getting over them just took time to familiarize herself with how boats work until she got to the point where she knew that nothing bad was going to happen when the boat rocked, or heeled or whatever.
At the end, my wife's dream isnt really the same exact dream as mine. But there is enough overlap that we are both going to be on the boat cruising in the Caribbean. We both win.