Synonyms

Important - essential, significant, imperative, vital, valuable, critical

Very - excessively, severely, highly, extremely, immensely, utterly

Negative - adverse, alarming, unfavourable, risky, serious, bad

Understand -  comprehend, recognise, grasp

Good - beneficial, satisfactory, excellent, acceptable, positive

Believe - maintain, argue, perceive, claim, feel, think

Dangerous - hazardous, perilous