I don't think love conquers all. I believe the definition of love is what determines whether love conquers all or not. If we go by your definition of love, then love conquers all, but if we go by the worlds definition of as strong attraction toward another person, then this love can't conquer all.
Strong attraction is a very important factor in whether a relationship works out, but there are way too many other factors that could overcome the power of attraction, such as different values and personality flaws, and cause the relationship to turn sour. I know someone who is/was strongly attracted to his girlfriend, but their relationship turned unhappy a long time ago, and it's only gotten worse since then. They've been together for several years, so there's a lot of attraction, but it is by no means a happy, healthy relationship. They've tried to resolve their problems, but their personal issues keep tearing them apart. It's really painful to watch.
So by that definition, no, strong attraction is not a guarantee of a happy and healthy relationship in the end.
This brings to mind the ordeal my aunt had with her husband. They were young and 'in love', but because they were not serious believers, they did not really have the love of God in them. This young attraction began to fade with time, and as I speak to you they are divorced. It breaks my heart when I remember this, knowing that if only they had the love of God in them, they probably would have been together today.
Giving your life to Christ has so many benefits, both in this world and in eternity.
You make a very good point. The world has it's definition of love but then there's God's definition. So yea you are correct. God's love conquers all but the world's love is powerless.
Yepp strong attraction to someone is not enough. God's love gives you the power to endure.