I'm trying to understand the difference ETFs and index funds in terms of selling them (if you want to get rid off them quickly for any reason).
As far as I understand, if you want to sell an index fund you know 100% sure that you will sell it the same day to request it, when the market closes (so you might need to wait some hours, with all the fluctuation that might involve).
On the other hand, ETFs are traded like stocks, so if you want to sell it you might find that no one wants to buy it. If you need to sell your ETF fast because of an emergency, you might have problems. This is the reason you need to pay attention to the ETF's bid-ask spread, to be aware if you will find easy to sell it if you need (if the ask is high, many people will be willing to buy when you want to sell).
Is the above correct, specially in terms of the problems you might have when you want to sell?