This word uses the kun'yomi reading for 真 and an irregular reading for 似. You've already learned the reading for 真, but here's a mnemonic to help you with 似:
What are you impersonating? A horse! You gallop around neighing (ね) at the top of your lungs! That's a pretty good imitation.
I am having trouble because my four-year-old daughter imitates everything she sees.