I am sad to hear that, Mey, but some cats just cannot stand children. It is probably nothing wrong with the hearing, more the opposite, in fact. Children have high-frequency voices that can throw some cats into a frenzy. And if she is fearful anyway, then the boisterous nature of children makes it even harder for them to cope.
Good that you found another nice person to take her, and had the strength to give her away. I am sure she will be happy with your cousin and who knows - if the winter comes, Hondje might decide to return to the humans, since you provide food and central heating
I am having a pretty tough time, currently: I have to move next Friday, and was told everything would go fine with the house, but now it seems there is a hitch and I might not be able to move in there next week. This would be a major pain in the neck, not so much for me: I can go into a B&B and the furniture gets stored. But my plants and cats.... I will have to find a place for them until I get something permanent (more or less), and my cats are like Muis: Very shy and frightened with people. I'd hate to have them send to a cattery for what looks to be weeks on end....
Please send me some positive energy to dissolve this hitch