So, to be sure, Rebecca is the blonde girl in church. At first u just have to talk with her to get lvl 1, then spend time and talk for lvl 2. Again spend time, and the task will be to recruit more girls for guild, that wud be Shino (in the bar) and Lucy (cat girl, in dojo at night). Then next quest shows up; "Find Jimmy", u will get another girl with that. After that, task is to "visit Rebecca at church" - this gives lvl 3. Spend some time with her, and (the task) "visit her in the evening", this will give lvl 4.
I hope it will help u.
