Several thoughts/pieces of advice:
First, find out what the true comps are. The discrepancy between assessment and list price is odd, but there could be a lot of reasons for it--everything from an old tax assessment (maybe that's what they sold for 3 years ago) to simply a vastly overpriced unit. You really, really need good comps to know what the real value is. It's good that you've seen nearby condos, and are basing your initial price on those. But you still might be off by 10%, 15%, or more. So: Get good comps.
Second, don't worry about your husband's advice. (Hey, Realtors know that wives make most of the decisions, anyway! I'm only partly joking; women really do make those decisions--to buy or not to buy--far often than guys. And that's why Realtors really do pay attention to women. Now if only car salesmen could learn the same lesson...)
But my point is: Do not worry about insulting a seller. Never. It's your money. It's a place where you might live. It's your financial future. Look: If you're prepared to move on anyway if you can't get it for the "right" price, what do you care if the seller's insulted? The seller will have 3 options when he/she receives your offer: (1) Accept, (2) Counter, or (3) Reject. If he/she counters, it indicates some level of interest. If it's rejected, you didn't want the condo at that high price anyway. And if it's accepted, you get the condo for your price.
And think of it this way: The seller should be insulted by the people who have looked at the condo and not made an offer. You're indicating you like the condo enough to go to the time and effort to make an offer.
So get the comps, then make an offer based on those comps and your level of interest and ability to pay.