INFJs are so adorable, always worrying about how others are feeling, or whether they might make people uncomfortable. It is one of their most charming qualities. I don't know if you are looking for advice, but if you are, here are my suggestions.
For any empathetic INFJ who worries about putting unwanted pressure on a potential mate, I suggest that the solution might be to declare your own feelings in a matter-of-fact way, without imposing the expectation for a response. Just tell the person you are interested in him/her, and let the other person decide what to do with the information, without making it a question or a demand. Instead of saying, "Will you be my girlfriend?" say "I would choose you if I were given the opportunity," and leave it at that.
I know there might be the implied expectation, but if you are really worried, there are ways of being subtle or ambiguous about it, in order to give the person a way out of having to reject you directly in a worst case scenario. I'm not saying this is the best option, but INFPs (people like me) tend to drop hints repeatedly and watch for signs that indicate whether those hints are being received positively or negatively. This serves several purposes: It allows us to retain hope rather than being crushed by direct rejection, and the hope of some vague possibility sustains us in times of emotional drought; It allows us to avoid inconveniencing those we care about; It sometimes leads to a very natural flow of events in which a relationship happens almost automatically, without any pressure on either side. Some INFJs might lack the necessary subtlety, or might consider such an approach irritating. Also, it only works on people who are especially perceptive. A person who doesn't understand might think of it as playing mind games, even though some of us take the approach quite seriously. It rarely works on __TP types, so if the person you are pursuing is, for example, an INTP, then s/he might not even notice. Anyhow, it's still an option, if you are trying to win the heart of a fellow NF.
Realistically, I doubt that most people would be disturbed by being told directly that they were liked, even if it turned out that they didn't reciprocate. As long as you aren't being pushy, and as long as you aren't treating the person in a dehumanizing manner, giving him/her the option of accepting or rejecting you doesn't have to be uncomfortable or awkward.
If you allow an easy way for the person to avoid having to address the matter directly, while still being as honest as possible, the fear of causing discomfort or awkwardness can be eliminated entirely, although trying to get this perfectly right can be a little tricky.
Maybe I am wrong, and maybe I have unknowingly caused people distress by being too open or too mysterious about my feelings in the past. There is a certain balance to guessing what will work best in any specific situation. Admittedly, I am not socially skilled, and I might not always know when I have made others uncomfortable, unless they are at least a little expressive, but I have gotten into some good relationships with people I still consider worthy by using a sincere approach, or a subtle one, depending on the person, and of the people who have rejected me before things got to that point, I doubt many felt particularly awkward about it, since most of them remained close friends with me even after turning me down romantically. I suppose that is one of the advantages to the fact that I am only attracted to people with whom I already have some kind of preexisting intimate connection, such as a strong friendship or a sense of being interconnected through shared values.
One thing I would like to mention, which is only partly related, is that there can be a downside to the tendency to avoid making other people uncomfortable, despite how refreshing the quality can be for those of us who are used to having our sensitivity violated by those who don't care at all. The avoidance of other people's discomfort can be a problem when a necessary confrontation is postponed for so long that it becomes a bigger disaster, especially when the feelings that are being withheld are negative. In such situations, the fear of causing others discomfort can cause a peace-loving person to quietly tolerate unpleasantness while the oblivious source of that distress continues to unknowingly harm him/her without meaning to do so. At the peace-loving person's breaking point, s/he may withdraw unexpectedly, causing more harm through abandonment or sudden cruelty than would have occurred if the problem had been addressed earlier. (The INFJ doorslam can be very painful from the other person's perspective.)
My last boyfriend was most likely an INFJ type 9, or at least seemed so to me, with a double helping of the non-confrontational tendencies I generally admire so much, and I think people who have that very attractive combination can be accidentally dangerous because of it if they aren't careful to remain honest about their own feelings in times of stress. (Admittedly, my being openly sensitive can make it especially difficult for such people to do so.)