Search doesn't show all the good results on my website

[MDKSocks]

(1) Ok so I have a question about my search on my website itself. I have an app installed that shows recommended searches. If I search konijn (rabbit) it shows that I have 3 kind of socks with rabbits on it. 

(2)But if we press enter and we go to the actual search results we only get 1 of the 3. The problem is that the other 2 have the namen Konijnen (plural). But if you search konijn the socks with the name Konijnen don't show up. 

If I search konijne then he finds them. So my guess is that the he takes 1 letter margin, is it possible to change this? So that when I search konijn that he also finds words like: konijnen, konijntje, konijntjes etc...

I could just change al the product titles to simpler words, but I just hope it is possible to change the search actually. Because more search results = more sales I guess.

Maybe there is an app that does this? Or a simple change in code?

 

[MDKSocks]

Any ideas?