、。
She held back her anger and smiled sweetly.
Literal
She [topic-は] anger [object-を] held-back, warmly smiled.
Two features stand out. First, the masu-stem conjunction こらえ (from こらえる, 'to endure / hold back') joins the clauses with a literary, composed tone — fitting for someone masking their emotions. Second, にっこりと is a 擬態語 (state mimetic) specifically for a warm, genuine-looking smile — ironic here since the smile conceals anger. 微笑する ('to smile gently') is more refined than 笑う ('to laugh/smile').