Homura has to be very careful around Madoka now; she can't come on too strong because that only confuses and scares her. Fear is the last thing she wants in Madoka's eyes when she looks at her.

But she also has to be careful, because if she doesn't, then she's going to lay her head against Madoka's shoulder and just bawl, beg her to believe, ask her to wrap her arms around her and tell her that it will all be okay. Tell her it's been worth it, tell her that this time it's going to work.

But that also qualifies as "too strong", so Homura can only look at her and pine.