Go on a really nerdy tangent (something you're invested in. Don't just talk about something totally random). If they don't understand or get mad, it wouldn't have worked out anyways.
Ask if the other person wants a monogamous relationship, a polyamorous one, or something in-between. If you disagree about what you want, move on to someone else who wants what you want.
Think, "How can I get the job of her boyfriend/girlfriend?"
Yes, a date is not a shopping outing, it is a job interview. Market yourself as someone interesting and useful to the company. Change her mind from "Why should I choose you?" into "I definitely want him in my team!"
If there is a store that has a lobster tank, take them there to watch the lobsters fight. Otherwise, surprise aquarium visit as all people love aquariums
Remember that the rewards from a relationship more or less match the amount of effort both (or all) partners put in. Also, loving someone does not mean you should trust them, and finding them untrustworthy (or unreliable) does not mean it is wrong to love them.