bolster

(v) – If you bolster something, you improve it or "lift" it. You can bolster someone's feelings or confidence by helping them to feel better and more positive.

• Synonyms: aid, assist, help, boost, strengthen, support
• Antonyms: hinder, obstruct, stymie
• Etymology: Before 1200, from Pre Germanic bolkhstraz, which comes from the PIE root bhelgh- meaning "to swell" (this is where we get the word belly!)
• Example: A helpful friend can really bolster your confidence.