Hi Krstofer
Obviously you can see if it selfs easily enough...the pollen grains are very small so I use the sophisticated method of just rubbing a finger around in small flowers like that which will spread the pollen onto the stigmas.
None of the above will work in terms of crossing, but alien pollen may then cause it to allow selfing. Some Passiflora, such as some of the P. murucuja clones, are not self fertile, but when foreign pollen is applied they somehow set fruit without the pollen giving any genetic input. So you can think you have hybrid seed, when in fact you just have selfed seed. This phenomenon has been observed & much discussed with regard to a number of Passiflora & other plants. It is called 'apomixis', the ability of some plant species to reproduce asexually by their seeds. Usually all the offspring will be identical clones of the mother plant, but some genetic variablity may occur as there are different ways that the normal reproductive process can be short-circuited.
Myles

Here is a link that might be useful: Passiflora hybridizing