One suggestion - I think I would prefer "he'd never make her feel unhappy for a moment" (something she was sure would never happen in the future) sounds better after "Ikuko knew". If she was talking about the fact that he had never made her feel unhappy for a moment in the past, you wouldn't really need "Ikuko knew". The link is made by the use of the word "that" before "he'd never made" because it effectively says: "Ikuko knew that she liked being with Hiroshi and she knew that he had never made her feel unhappy". That doesn't work for me. If you remove "that" you are left with "Ikuko knew that she liked being with Hiroshi and he had never made her feel unhappy", which sounds better.
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