Why do you think people get a Keyblade? What marks a strong heart?
In Sora’s case, he kind of happened to be in the right place at the right time, while both Riku and Kairi had a Bequeathing — even if Kairi’s was accidental
I tend to think of a strong heart as someone with a lot of determination, myself :) what’s your thoughts?
thats a interesting question, its never explained how or why do people get keyblades beyond bequeathing and i doubt that sora being chosen for being on the right place at the right time is a unique event, daybreak town was filled with young keyblade wielders and i think thats way too many for the MoM and the foretellers to have bequeathed all of them and other than characters hitchhiking other characters's habilities to wield keyblades throught their connection (roxas and xion with sora and probably vanitas with ventus) being lucky is the only way we saw happen(tho one of the few things we knew about ML was that it would play a bit with the concept of keyblade wielding bloodlines) :P that being said having a strong heart certainly has to do with it and probably has something to do with how good you are at it as well
as for having a strong heart while determination certainly plays a role into it i do think that there is something more important than it when determining one's strenght of heart:the hability to connect with others
this is a major theme in KH(well duh "my friends are my power" is often quoted in the series) but its also something that was shown with most if not all strong keyblade wielders, both Xehanort and Sora are shown to have a great hability to connect with others with xehanort often exploiting said connections to further his plan(the organizations, Eraqus, ansem's apprentices, etc) even in dark road he is shown to get along well with the entire class before everything went wrong, and i dont think i need to explain sora right? but even without counting them the bonds to others are often shown to affect one's hability to wield the keyblade, with certain characters(mostly riku tho ansem, anti form sora and the darklings from KHUX probably also apply) even going as far as to lose their hability to wield a keyblade as their heart grows weaker and darkness begins to control them(while strong hearts seemingly having the hability to controll darkness instead as noted by riku, terra rage form sora and notoriously:xehanort)
Riku loses his keyblade to sora when he is left alone as sora regains his friends in KH1, he doesnt even get a keyblade back until he is reunited with sora and kairi in the end of KH2
Terra is isolated by Xehanort(both in a literal way as xehanort 1v1 terra in the pillar while vanitas deals with aqua and ven and in a psychological way by sowing discord amongst the wayfinder trio) before getting norted, and its his connection so aqua and ven that allows both him to keep his will bound to his armor, and return to his body after being trapped in the guardian for over 10 years
Roxas gives riku Oblivion due to Xion's interference, this almost kills him until riku decides to allow roxas to get it back for some reason(he was on the ground riku why did you let him get oblivion back?!? XD)
the only time where we see sora truly powerless(ever since i think KH1) is when he witnesses his friends dying to the heartless tide wich leads to him having a mental breakdown, this does not affect riku as he knows that if they survive this they can get their friends's hearts back
its aqua's connection to terra and ven that keeps her sane in the realm of darkness for over 10 years(and she would have made it if ansem hadnt pushed her over the edge... literally)
the chains that Terranort uses to bind aqua ven and sora in their confrontation are stated by himself to be their bonds wich they will never be able to break
vanitas who could be a exception to the rule seems to feel the pain of his own unversed as they are struck down(i think that was only shown in non canon material so dont quote me on that one)
even in KHUX, ava's mission is to pick keyblade wielders with potential and enlist them into the dandelions who were above the divisions of unions at the time
and of course as mentioned before:weaker hearts seem to have a harder time dealing with darkness thus becoming heartless easier and we never saw a heartless with a keyblade(other than riku-ansem, but ansem was using riku's body in that ocasion :P)
so my conclusion:while having a strong heart probably deals with several factors(Determination, quantities of light and darkness and etc) being able to connect to others and have people by your side is absolutely a sign of a strong heart