The most difficult thing is the decision to act; the rest is merely tenacity.

EACH BEST MEANT TO BE THE ABBREVIATED CAPS FROM THE WORDS ABVOVE

Determine, decide, resolve, solve, settle, unravel

• Come to a conclusion after consideration (Dce)
• Come to a conclusion for a problem (Rse)
• Come to a conclusion in agreement (Ste)
• Come to an answer for an issue (Sve)
• Come to an explanation for a mystery (Url)
• Come to a firm conclusion (Dme)

Murderous, difficult, hard, strenuous, arduous, onerous, exacting, taxing, debilitating, grueling, laborious

• Needing much effort (Dft)
• Resisting pressure (Hd)
• Using great effort (Sts)
• Involving effort and time (Ads)
• Oppressively requiring effort (Ons)
• Mentally demanding (Tg)
• Demanding skill and attention (Exg)
• Requiring effort and time in a task (Lbs)
• Extremely tiring (Grg)
• Making weaker by time (Dbg)
• Extremely unpleasant (Mds)

Tenacity, persistence, determination, perserverence

• Deternined to exist (Tny)
• In spite of difficulty (pse)
• In good purpose (dtn)
• No delay in achievement (Pse)

Just, only, merely, simply, solely, purely, merely

• Nothing more besides (O)
• Exclusively (P)
• With no limitation (A)
• Not involving anyone (So)
• In short summary (Si)
• Based on what is right (J)
• For one purpose (M)