It means that he(Eric) is saying and doing everything he can to prove that he loves her and will always be there (she ought to know by now) so he's doing all these things to make her know but he's not getting the reply he wants so he's on the verge of giving up when she (Marsha) tells him to listen. She knows that he loves her and she loves him too but for now just know that she is there but to more so to take it slow b/c she does not want to mess up this good thing. Especially because he mite be the one.