"guarantee myself" is a correct phrase and can be used in written English.
It is usually used to convey the action of ensuring or securing something for oneself. Example: "I will guarantee myself a successful future by working hard and staying focused on my goals."
"If I had watched our games the last two weeks, I might have made the guarantee myself," Charlie Weis, the Notre Dame coach, said at a news conference.
Having played Test rugby for both countries – I was born in Queensland into a family with deep Irish roots – I think I'll be able to guarantee myself an interesting emotional ride as the rugby unfolds.
"I think if I lifted [in Glasgow] tomorrow I'd win, so hopefully next year I'll guarantee myself a gold".
I majored in communications because if I did not guarantee myself the opportunity to function throughout life as a talented, creative person, I was, by design, guaranteeing myself a life of misery.
My ideal situation was for him to tell me I could guarantee myself a spot on the 2018 or 2019 stage--then I could still do it, but not now, and I could be more experienced when I did it, and most importantly, I could put something super hard and stressful off into the far future when it was a totally different Tim's problem.
But in saying this, I know from experience that I have guaranteed myself a barrage of hate mail.
I forced a no-cooperation agreement with the government, practically guaranteeing myself more jail time, so that i would never speak against my friends or my site".
One bank asked for personal guarantees from all the stockholders, even though I was willing to guarantee the loan myself.
Also, how can I turn down the opportunity to guarantee a steak for myself and my family, but most importantly, myself?
I guarantee that most scientists, myself included, would love to make their reputation by refuting the whole notion of global warming.
Those minutes, after all, are 90 guaranteed minutes to myself.
