Strategy for selling a house - what is the best way to proceed?

Overall, I would probably not advertise it just yet, but wait a little longer.

Thank you very much for your insightful contribution!

My husband and I have also been thinking about it for a long time today. It comes down to the fact that we will only advertise the house after construction has begun.

I replied to him 20 minutes ago to his 4-day-old email, asking him to kindly share his price expectation with me. 5 minutes later I already had a reply with a price expectation, to which I won’t even respond anymore

Yes, but (substantively) not now. Emotions – no matter how understandable and justified – should be separated from business. By his behavior, he gave you a very valuable tip about what conduct he considers okay – you should make use of that: In the first step, you contact him back (promptly now), thank him for his offer (completely without addressing its amount) and promise him you will "gladly take it into consideration." Then you offer the property. You name a price basis "negotiation basis" – my recommendation would be 115% of the price you consider appropriate based on the estimates, rounded (down) to the next reachable XX9,000. It is important not to mince words here, for example: "Please only contact me after you have spoken with your bank. Regarding ‘What is the final price, colleagues,’ I recommend another venue." For contacting you, use a separate mobile number for this purpose; prospective buyers should initially only send an SMS with [price expectation], [name], [their_email_address]. In step three, I would inform the neighbor: "I have received some offers significantly above your first offer. However, I also want to deal fairly with you and give you up to 14 days to express your continued interest by submitting a reasonably increased offer." Provided he knows your usual diction, of course you wouldn’t phrase it so bluntly. Afterwards, in your place, I would favor his last offer as long as it is not clearly more than five grand below those from the previously unknown interested parties. Pecunia non olet, and you’re not supposed to want to marry the buyer.

Maybe one could add to the ad "...available from spring 2022...". We did it that way and all interested parties understood that they could not move in "tomorrow".

Yes, but not (substantively) now. Emotions - no matter how understandable and justified - should be separated from business. He gave you a very valuable tip with his behavior about which conduct he considers okay - you should use that:

I had emotionally closed the matter with him :D but I’m happy to learn! Thanks :)

Maybe you could add in the ad "...available from spring 2022...". We did that and all interested parties understood that they couldn’t move in "tomorrow".

How much time was on your side and did you offer your interested parties a concession on the price/rent?

My brother was once interested in a house; on his part, moving wouldn’t have been stressful (he already lives with his family in a spacious condominium). The sellers wanted the money "immediately" to then pay for an age-appropriate property. However, the timelines were so open-ended – it was not at all foreseeable when they might find such a property – it was then like Russian roulette. That was one of the points where it ultimately failed. Depending on how scarce the properties are, you might also find a buyer who waits. Your investor was actually ideal in that regard; you would just have paid rent and could have stayed as long as your construction takes. But the fact that he doesn’t pay like an "owner-occupier" is of course to be expected. Here “stress-free” stands against revenue. You have to weigh for yourself what that’s worth to you. It will certainly cost significantly more than the 5 grand suggested by .

I had made peace with him internally

Yes, but when it comes to emotions, as a businessman I never hold my wallet hostage ;-)

Here "stress-free" stands against revenue. You have to weigh for yourself what that is worth to you. It will certainly cost significantly more than the 5K brought up by @11ant.

I was referring to the tolerable difference in my opinion compared to the otherwise most attractive offer from a "previously completely unknown" interested party.