What's the point of even having a partner if you can't rely on them for anything? Being someone that women can count on is definitely one of the most attractive qualities you can have. If you always answer your phone, are ready to help out in a crisis, and don't shirk your responsibilities, women will appreciate that and it will definitely make you great boyfriend material. Nobody wants to settle down with someone flakey.
Do you regularly miss important calls from people in your life who need your help? Maybe it's time to start paying attention and being a bit more reliable. We're not saying you have to be a slave to the people you love, but being somebody people can count on is a great quality that women find very attractive in a man.