That's the thing about good intentions. There's a certain road...

Speaking as someone who does remember being adopted, the thing that made the difference was, yes, the presence of good intentions, but also the reiteration of them. Not in word, but... action.

[He knew Bruce and Alfred cared about him, because, despite being two of the stiffest, stuffiest, most austere, boring adults to ever walk the Earth, they tried. Their stiff stuffiness actually highlighted how much they'd tried to include him in their lives, whether it was by teaching him about their own interests or just never missing a birthday party.]