1) Bolsters the confidence of 2) Convinces 3) Eases the misgivings of 4) Frees from all doubt 5) Frees from doubt 6) Gives confidence to 7) Gives peace of mind 8) Guarantees 9) Helps free from doubt 10) Informs positively 11) Leaves no doubt about 12) Makes certain 13) Makes certain of 14) Promises 1) Sews up