I'm going to take a different tone than several of the other responders and say go ahead and talk to this person. Personally, I've had plenty of great "getting to know you" talks with other NF, and in particular with other ENF's. Just be wary of treating this person like some sort of science project, that may or may not get very far.
Reactions I had: be wary of some very real IE PJ and FiNe FeNi differences. For example, as an EJ one is more likely to think that people should put things out there, E, and be declarative in the process, J. INFP's tend to have all sorts of interesting observations, thoughts, feelings, reactions, etc, but we aren't likely to share them with you unless you specifically ask. Also, be wary of trying to "put this person in a box", I think we INF's tend to really enjoy thwarting people's efforts to see us in only certain ways. For example, if you wanna see me as some boring non-social person I'll either 1) totally exaggerate that perception to make you believe it and hence go away faster, or 2) totally go the other extreme and try and fling all sorts of things in your face that are the opposite of your perception. In addition to the box thing, be wary of being/coming across judgemental, we don't take well to that either. We tend to have very deep, complex, perhaps even convoluted personalities, so when people do surface probing and try to slap a label on us, there is far more going on below that label, perhaps much of which would contradict that label.
Tolerate and see the value of Fi. Tolerate and see the value of Ne. Both may really push you, especially the Fi. I think that ENFJ's often see themselves as social leaders, which we as INFPs may or may not go along with. Be prepared to drop the reins and just go with things however they may flow. Don't be one iota surprised if after talking to this person you feel a lot less worthy, less impressive, less self-actualized, and not as good/nice of a person as you thought you were. As I've read ENFJ's saying "Fi really puts me in my place." I interpreted their context as saying "I thought I was a pretty good/nice/moral/developed person, and I am, but they are definitely better at it. Fe seems to make people socially adept, Fi, especially well-developed Fi, tends to lead to much more "saint-like" attitudes.
I've had really good experiences with ENFJ's. Fi and Fe can be extremely complementary. Ne and Ni can both share insights and possibilities. Be respectful, be open, listen, share. If so, you should be fine, and this may be among the most eye-opening conversations of your life. If nothing else, it should be pleasant and enjoyable.
One last thought: ENFJ's seem to tend to have definitive plans, aims, and goals, and be actively working towards accomplishing those. INFP's are FAR more just in the moment. We tend to go with the flow wherever it may take us, and just use our values to understand what to do in that moment. Be wary of looking down on INFP's for not having strong enough concrete life plans, or for not taking pre-planned actions that might further us towards our ideals/goals.