Actually - the research I am doing shows that a single, clean stab wound through the heart *can* be indicative of suicide. In these cases, people 'fall' on a knife or find some other means of driving the weapon into their bodies. It's rare, but happens. And when mental illness is involved, people of both sexes can do some truly horrific things to themselves, things that make this case look utterly tame...
(but yes, women do generally choose less violent methods, you're quite right there)
I just don't think suicide is what happened, here. And there were several people both directly and peripherally in her life who would know exactly how to stage a suicide scene, and what police *might* look for when investigating an apparent suicide... (that's IF the police were actually looking, oy).
There are many reasons I think this was a cleverly staged murder, but here's a big one -- for someone to so meticulously wrap a knife handle (and people who are suicidal can make meticulous plans) and then basically choose to play 'pin the tail on the donkey' with a massive knife, blindfolded, just seems extremely odd. Most self-inflicted stab woulds show signs that the person has bared their skin over the intended stab site - they want to get it right. So they need to *see* what they are doing. And this when their own hand controls the knife -- a knife attached to a wall is way less certain, and the momentum necessary to drive the blade through her chest means she must have backed up at least a little ways. This is so hit-and-miss, it doesn't gel statistically, nor with the meticulous knife-wrapping. Also, an apparently convoluted suicide method, from a person who journalled a great deal and was a known list-maker -- yet there's no note, no instructions on care for her beloved dog... no apology to her beloved parents... nothing. It does not gel, at all, in my mind.
But why stage it, if her death was staged, in this *specific* way? Well, it would appear that she didn't die in the house, a big bonus if you plan to move a new lover in quite soon (which happened) and sell it quickly (which also happened).
And it'd be a good way to cover up a stabbing murder, eh.