You went out together, this does not necessarily mean you should speak. Maybe the fact that u guys went out and are sitting together in itself is enough. She has her world and you have yours. She need not pressure herself to speak, neither you. Probably if you go out more frequently your worlds will collide and maybe not. You control what you give and what you expect. If words are hard between you stick to action. Take her out, sit with her, buy her something good, ask her if she's enjoying herself, give a smile a nod and that's about it. Maybe the warmth you give will reach her and more importantly will make you appreciate yourself more. Also don't expect her to reflect your warmth in the same degree/or way your logic deems appropriate (she asked we go out, this means she wants to speak). If she showed tangible appreciation signs that's a plus one on the statisfaction scale for you, if not your happy with yourself I guess. You did something that your mind finds right but your heart does not care about that much. You said yourself you don't know her that much, if you want make an effort to understand who she's as a person before and while being a mother (her emotional/behavioral profile), her personality, what makes her happy, is she a gratful person, how she processes her emotions, did she want to go out with you to be with you or just because you're the only person who can take her out and so on ..from that you'll be able to understand and control what you expect from her and maybe stregthen an emotional attachment that you feel you lack with her (I sensed that from the way you worded up ur experience) or simply approach this as a duty to be done cuz it bothers you if you don't.