Your question is largely biased and no one without your subjective body of ideas would be able to answer it, me included.
Instead, this is an answer to the question what is love, essentially based on the book The Art of Loving, by Erich Fromm, which foundations can be found in the work of most philosophers that addressed the subject.
Love is essentially an attractive interaction between two individuals, which results from an exchange of largely subjective values.
It is an exchange of values because love implies giving and receiving. Most people associate love with receiving (affection, sexual pleasure, security, money, etc.), but that's only part of the history. Giving is also pleasant because in a healthy relationship, giving causes the other to react in a non-linear manner, and return more than received.
This is a quite silly but useful example. Suppose I love my wife, so I feel giving her a kiss, so I do it. Since we have a healthy relationship, she feels pleased with the kiss and feels the need to respond giving more than received (the causal reaction is innate to human interactions). So, she give me two kisses. I feel extremely pleased, so I need to react, with something that exceeds what I received. So I give her four kisses. Etc.
That leads to the other part of the concept: when an individual receive more than what given from someone, the individual will feel attracted to that other. This is quite evident. If you go to the supermarket, get a delicious apple for a great price, you will feel attracted to that supermarket, to that neighborhood, to that way of life.
Attraction produces repetition. Evidently, if I get pain from my wife, I will reject her in order to avoid repetition. But if I receive values that make me feel good, I will feel attracted to her in order to repeat receiving such values.
When receiving is not compensated with giving, the relationship gets damaged and will soon break (one side creates rejection, which is enough to break a relationship). If my wife gives me kisses without any reaction from me, she'll soon stop giving them. I know this sounds utilitarian, but that's how it works. We all give things due to our internal need to receive. People who learn to give without receiving, as a permanent life rule, are just applying the fundamentals of the rule in order to get a nice life. But when generous people are not compensated, they get distanced (careful! you want to have generous people around you, and they are not easy to find). We give in order to receive, and only two individuals who know how to permanently give more than received can make a long lasting relationship.
In multiple cases, people need to suffer (usually, when they have suffered during childhood). So, people might choose a harmful partner in order to get satisfied and repeat suffering. That is love for them. That's why the definition includes the word "subjective". Of course, there are a lot of twisted forms of loving exchange (love with the devil fits probably well here).
When you speak about love with the devil, I personally don't imagine how it works. It is difficult to conceive a devilish entity with whom exchange kisses, laugh, listen music, have a drink, get lunch in the grass, go traveling, go biking, cook, make music or have a nice evening, that's quite subjective to your ideas, so you must get your conclusions based on the meaning of love here.