If you’re still struggling, just imagine instead of initiating sex, you’re making them a cup of tea.
You say “hey, would you like a cup of tea?” and they go “omg fuck yes, I would fucking LOVE a cup of tea! Thank you!*” then you know they want a cup of tea.
If you say “hey, would you like a cup of tea?” and they um and ahh and say, “I’m not really sure…” then you can make them a cup of tea or not, but be aware that they might not drink it, and if they don’t drink it then – this is the important bit – don’t make them drink it. You can’t blame them for you going to the effort of making the tea on the off-chance they wanted it; you just have to deal with them not drinking it. Just because you made it doesn’t mean you are entitled to watch them drink it.
If they say “No thank you” then don’t make them tea. At all. Don’t make them tea, don’t make them drink tea, don’t get annoyed at them for not wanting tea. They just don’t want tea, ok?